The number of patients with periodontal disease in China is large, and the ratio of doctors to patients is seriously imbalanced, especially in the insufficient number of periodontal specialists and periodontal teachers. Strengthening the cultivation of professional postgraduates in periodontology can effectively solve this problem. This paper summarizes the experiences of Peking University School and Hospital of Stomatology in the teaching of periodontal postgraduate students for more than 30 years, in cluding teaching objectives formulation, teaching resources allocation and enhancement of the quality control system of clinical teaching, for ensuring that the periodontal professional postgraduates could reach the expected level after training. This formed the current "Peking University Model". There are both opportunities and challenges in clinical teaching of periodontal postgraduates in domestic stomatology community. The authors hope that the continuous exploration and improvement of this teaching system will promote the vigorous development of clinical teaching for the postgraduates majoring in periodontology in China.

Humans ; Otitis Media, Suppurative ; Chronic Disease ; Biofilms ; Otitis Media

OBJECTIVE: To evaluate the characteristics of severe periodontitis with various number of tooth loss during 4-year natural progression, and to analyze the factors related to higher rate of tooth loss. METHODS: A total of 217 patients aged 15 to 44 years with severe periodontitis were included, who participated in a 4-year natural progression research. Data obtained from questionnaire survey, clinical examination and radiographic measurement. Tooth loss during 4-year natural progression was evaluated. The baseline periodontal disease related and caries related factors were calculated, including number of teeth with bone loss > 50%, number of missing molars, number of teeth with widened periodontal ligament space (WPDL), number of teeth with periapical lesions and etc. Characteristics of populations with various number of tooth loss and the related factors that affected higher rate of tooth loss were analyzed. RESULTS: In 4 years of natural progression, 103 teeth were lost, and annual tooth loss per person was 0.12±0.38. Nine patients lost 3 or more teeth. Thirty-four patients lost 1 or 2 teeth, and 174 patients were absent of tooth loss. Molars were mostly frequent to lose, and canines presented a minimum loss. The number of teeth with WPDL, with periapical lesions, with intrabony defects, with probing depth (PD)≥7 mm, with PD≥5 mm, with clinical attachment loss≥5 mm, with bone loss > 50% and with bone loss > 65% were positively correlated to number of tooth loss. Results from orderly multivariate Logistic regression showd that the number of teeth with bone loss > 50% OR=1.550), baseline number of molars lost (OR=1.774), number of teeth with WPDL (1 to 2: OR=1.415; ≥3: OR=13.105), number of teeth with periapical lesions (1 to 2: OR=4.393; ≥3: OR=9.526) and number of teeth with caries/residual roots (OR=3.028) were significant risk factors related to higher likelihood of tooth loss and multiple tooth loss. CONCLUSION In 4 years of natural progression, the number of teeth with bone loss > 50%, baseline number of missing molars, number of teeth with WPDL, baseline number of teeth with periapical lesions and number of teeth with caries/residual roots were significantly related to higher risk of tooth loss and multiple tooth loss among Chinese young and middle-aged patients with severe periodontitis in rural areas.
Humans ; Tooth Loss/etiology* ; Periodontitis/complications* ; Tooth ; Periodontal Diseases ; Molar

Toxin-antitoxin system (TA) is a genetic element widely found in chromosomes and plasmids of bacteria, archaea and prophages. TA usually consists a toxin that inhibits the growth of bacteria and an antitoxin that neutralizes its toxicity. Since the discovery of the first CcdB / CcdA TA in the 1980s, TA has been proved to exist in almost all sequenced microorganisms and plays an important role in maintaining plasmid stability, anti-phage and promoting biofilm formation. At present, TA is divided into type I-VIII, among which type IITA is the most widely studied. HipBA is a type II TA. The toxin HipA in Escherichia coli HipBA is a serine / threonine kinase, which inhibits protein translation by phosphorylating bacterial Glutamyl tRNA synthetase (GltX), and its toxicity can be specifically neutralized by HipB. Recently, it has been found that Escherichia coli HipA homologous proteins exist widely in microorganisms, and they form a potential novel TA with genes of the same promoter, in which HipBST has been confirmed by experiments. The toxin HipT and the antitoxin HipS in this TA are similar to the C-terminal and N-terminal of E. coli HipA respectively, and the neutralization mechanism and the substrate of the toxin are different from that of E. coli toxin HipA. This study summarizes the recent discovery of special TA, especially the neutralization mechanism of HipBST which widely exists in prokaryotes.

Bunyavirus is widely distributed, highly contagious, and has a high fatality rate. It is a negative- strand RNA virus that has a major impact on public health around the world. The development of vaccines and the search for drugs are the key to prevent bunyavirus infection. The nucleoprotein (NP) of viruses is necessary for the synthesis of viral RNA, which combines with viral RNA to form the nucleocapsid, participates in viral assembly and RNA transcription, and plays an important role in viral proliferation. In addition, NP also has B cell and T cell epitopes, which can induce cellular and humoral immunity, so NP is an ideal target for vaccine design and drug development. Given its abundance and specificity, NP is also commonly used in the detection of viral diseases. More and more bunyavirus NP structures and structures of NP-RNA complexes have been resolved. Researchers have discovered two important antiviral targets through these structures, the terminal arm and the RNA binding cleft. This paper reviews the function and three-dimensional structure of the bunyavirus NP and the research progress of NP as an antiviral target, in order to provide a theoretical basis for the prevention and treatment of the bunyavirus disease.

Objective:To assess the ultrasonographic features and potential diseases of fetal abnormal sylvian fissure(SF), and to explore the value of whole-genome sequencing (WGS) in prenatal detection.Methods:A total of 28 fetuses with a sonographic diagnosis of abnormal SF in Shenzhen Maternal and Child Health Hospital Affiliated to Southern Medical University between October 2018 and October 2020 were prospectively included. The fetal brain was evaluated by neuroultrasound and intrauterine MRI in detail. Amniotic fluid/cord blood obtained by amniocentesis or tissue samples from umbilical cord after birth were collected for WGS. Pregnancy outcomes and postnatal MRI were recorded, and neurodevelopment of live-born infants was followed up for more than 24 months after delivery.Results:During the study period, 28 fetuses with abnormal SF were identified, with a gestational age of 21.3-30.0 (24.8±2.0) weeks. Abnormal SF presented in MCD ( n=15, 53.6%), chromosomal anomalies ( n=3, 10.7%) or single-gene genetic syndromes ( n=3, 10.7%) with the affected fetuses showing developmental delay, hydrocephalus or leukomalacia ( n=4, 14.2%), corpus callosal agenesis with large interhemispheric cysts ( n=1, 3.6%), benign subarachnoid space enlargement with arachnoid cysts ( n=1, 3.6%), and multiple malformations ( n=1, 3.6%). Among the 15 cases with MCD, the most common pathology was lissencephaly/pachygyria, followed by schizencephaly, severe microcephaly, hemimegalencephaly with paraventricular heterotopia, and polymicrogyria. Abnormal SF presented bilaterally in 23 fetuses and unilaterally in 5. All cases were categorized into six types depending on SF morphology in the transthalamic section: no plateau-like or a small insula, linear type, irregular corrugated SF, Z-shaped, and cyst occupying type. In addition to abnormal SF, associated anomalies or mild variations were identified in all fetuses. There were 17 cases underwent intrauterine MRI, and 13 cases underwent postnatal MRI examination.And 25 pregnancies were terminated; 3 were born alive, and 2 had typical syndromic changes with poor neurodevelopmental prognosis. A related pathogenic genetic variant was detected in 57.1% (16/28) fetus, and the incidence of single nucleotide variants(SNVs) was 42.9% (12/28), among which de novo SNVs accounted for 91.7% (11/12). Conclusions:Fetal abnormal SF could be classified based on the ultrasonographic features of transthalamic section. Fetal abnormal SF may indicate MCD, some chromosomal abnormalities or single-gene genetic syndromes that may lead to poor neurodevelopmental outcomes, and may be affected by extra-cortical factors. It is suggested to carry out targeted prenatal genetic diagnosis for fetuses with abnormal SF.

Background: Cardiopulmonary resuscitation (CPR) strategies in COVID-19 patients differ from those in patients suffering from cardiogenic cardiac arrest. During CPR, both healthcare and non-healthcare workers who provide resuscitation are at risk of infection. The Working Group for Expert Consensus on Prevention and Cardiopulmonary Resuscitation for Cardiac Arrest in COVID-19 has developed this Chinese Expert Consensus to guide clinical practice of CPR in COVID-19 patients. Main recommendations: 1) A medical team should be assigned to evaluate severe and critical COVID-19 for early monitoring of cardiac-arrest warning signs. 2) Psychological counseling and treatment are highly recommended, since sympathetic and vagal abnormalities induced by psychological stress from the COVID-19 pandemic can induce cardiac arrest. 3) Healthcare workers should wear personal protective equipment (PPE). 4) Mouth-to-mouth ventilation should be avoided on patients suspected of having or diagnosed with COVID-19. 5) Hands-only chest compression and mechanical chest compression are recommended. 6) Tracheal-intubation procedures should be optimized and tracheal-intubation strategies should be implemented early. 7) CPR should be provided for 20-30 min. 8) Various factors should be taken into consideration such as the interests of patients and family members, ethics, transmission risks, and laws and regulations governing infectious disease control. Changes in management: The following changes or modifications to CPR strategy in COVID-19 patients are proposed: 1) Healthcare workers should wear PPE. 2) Hands-only chest compression and mechanical chest compression can be implemented to reduce or avoid the spread of viruses by aerosols. 3) Both the benefits to patients and the risk of infection should be considered. 4) Hhealthcare workers should be fully aware of and trained in CPR strategies and procedures specifically for patients with COVID-19.

Objectives: To investigate the prevalence and associated risk factors of tinnitus in Sichuan and Chongqing. Methods: We designed a tinnitus epidemiological questionnaire. The multi-stage stratified cluster random sampling methods was applied to obtain study subjects in six areas (Nanchong, Jiangjin, Fengdu, Yunyang, Suining and Ya'an), which were selected for epidemiological investigation. Home visit completion of epidemiological questionnaires was conducted. The trained investigators guided the respondents to fill in the tinnitus epidemiological questionnaires, and the epidemiological status of six areas on prevalence and risk factor was investigated. SPSS 22.0 software was used for statistical analysis. Results: Sampling population were 10 289, in which 9 273 were valid questionnaires. There were 4 281 males and 4 992 females, with an average age of 47.3 years, among which 34.83% (3 230/9 273) had tinnitus. 3.99% (370/9 273) were diagnosed with bothersome tinnitus. In a multivariable logistic regression mod, the following factors were associated with onsetting of tinnitus: sleep disorder [Odds Ratio(OR)=3.74] and noise exposure(OR=1.99). The risk of disease was lowest in the age of 30-40 years old, while the risk of disease was higher for people under 30 and over 40. In another multivariable logistic regression mode, the following factors were associated with having bothersome tinnitus: older people were more likely to suffer from tinnitus, sleep disorders (OR=4.68) and noise exposure (OR=1.56). Conclusions: The prevalence of tinnitus in Sichuan and Chongqing is about 34.83%, but most of the tinnitus is short-lived and has low loudness, which will not affect the patients. Only a small number of patients with tinnitus (3.99%) persist and affect their health and need treatment. The occurrence and exacerbation of tinnitus may be related to sleep, age, and noise exposure.
Adult ; Aged ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Prevalence ; Risk Factors ; Surveys and Questionnaires ; Tinnitus/epidemiology*

OBJECTIVE: To evaluate the gingival thickness and gingival biotype of gingival recession teeth of Chinese population. METHODS: A total of 112 non-molar teeth with gingival recession in 34 patients were included. Direct measurement, cone-beam computerized tomography (CBCT) measurement and periodontal probe method were used to evaluate gingival thickness and biotype. Gingival thickness was measured at 2 mm apical to the gingival margin. Direct measurement was performed with a caliper of 0.01 mm resolution and anesthesia needles attached to silicone disk stops. Gingival biotype was assessed by sulcus probing, if the periodontal probe was visible through the gingival tissue, the gingival biotype was thin; If not visible, the gingival biotype was thick. The differences of gingival thickness among different gingival biotype, tooth site and gingival recession type were analyzed respectively. Besides, the results of CBCT measurement was analyzed compared with the direct measurement. RESULTS: The average gingival thickness of non-molar recession teeth was (1.17±0.41) mm. The average gingival thickness of thick and thin biotype group were (1.38±0.4) mm and (0.97±0.30) mm, respectively, with statistically significant difference (P<0.001). The median of gingival thickness was 1.1 mm. Using 1.1 mm as the cut-off value of thick and thin gingival thickness group, the results matched well with the gingival biotype classification results by periodontal probe method (P=1.000). The average gingival thickness of maxillary teeth was significantly thicker than that of the mandibular teeth. They were (1.39±3.44) mm and (1.01±0.31) mm, respectively (P<0.001). The mean gingival thickness of MillerI, II and III degree gingival recession teeth were (1.15±0.34) mm, (0.83±0.17) mm and (1.26±0.56) mm, respectively, without statistically significant difference (P=0.205). The gingival thickness measurement results between CBCT method and direct measurement were without statistically significant difference (P=0.206). CONCLUSION In the non-molar gingival recession teeth, the cut-off value of gingival thickness to classify thick and thin biotype of Chinese population was 1.1 mm. The average gingival thickness of the maxillary teeth was significantly thicker than that of the mandibular teeth. Besides, CBCT measurement was an accuracy method for evaluating facial gingival thickness.
Cone-Beam Computed Tomography ; Gingiva ; Gingival Recession ; Humans ; Incisor ; Maxilla

OBJECTIVE: To investigate the role of growth arrest-specific protein 6 (Gas6) in the process of the migration and osteogenic differentiation of human periodontal ligament cells (hPDLCs). METHODS: After different concentrations of recombinant human Gas6 (rhGas6) were added to hPDLCs, cell prolife-ration experiment (CCK-8) was taken to observe the effect of rhGas6 on hPDLCs cell proliferation. Scratch test and cell migration test (Transwell) were taken to analyze the migratory ability of hPDLCs in different concentrations of rhGas6 groups. After osteogenic induction, real-time quantitative polymerase chain reaction (real-time PCR) was taken to detect the expression of the Runt-related transcription factor 2 (Runx2) and alkaline phosphatase (ALP). ALP staining was used to detect the amount of mineralized nodules. RESULTS: After adding different concentrations of rhGas6, there were no statistically significant differences in hPDLCs cell proliferation among the experimental groups and the control group at 24, 48 and 72 hours (P>0.05). After 24 h of scratch, the healing area in the 800 μg/L of the rhGas6 group was greater than that in the control group, but without statistically significant difference (31.06%±13.70% vs. 21.79%±9.51%, P>0.05). In the migration test, after 24 h, the number of hPDLCs cells which penetrated through the membrane in the 800 μg/L rhGas6 group was significantly higher than that in the control group (P < 0.01). After rhGas6 was added and osteogenic induction, Runx2 and ALP gene expressions of hPDLCs in the 800 μg/L group were significantly higher than those in the control group (1.60±0.30 vs. 0.91±0.10, 2.81±0.61 vs. 0.86±0.12, P < 0.01). After Gas6 was knocked down, the ALP expression of hPDLCs was significantly lower than that of the control group (0.39±0.07 vs. 0.92±0.14, P < 0.01). There was no significant change in Runx2 expression (P>0.05). After 7 days of osteogenic induction, the mineralized nodules formed in the Gas6 knockdown group were significantly less than those in control group (0.25±0.04 vs. 1.00±0.11, P < 0.001). After 14 days of induction, the staining degree of the Gas6 knockdown group was lower than that of the control group, but there was no significant difference (0.86±0.04 vs. 1.00±0.16, P>0.05). CONCLUSION After downregulation of Gas6 gene, mineralized nodule formation was reduced and ALP gene expressions were decreased in the early stage of osteogenic induction (7 days). After addition of rhGas6, Runx2 and ALP gene expressions were increased and the number of cell migration was increased, suggesting that Gas6 might play a promoting role in the migration and osteogenic differentiation of human periodontal ligament cells.
Alkaline Phosphatase ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Humans ; Intercellular Signaling Peptides and Proteins ; Osteogenesis ; Periodontal Ligament