[Correlation between weight variability and the risk of diabetic nephropathy in patients with type 2 diabetes mellitus].

Objective: To evaluate the relationship between different indexes of weight variability and the risk of diabetic kidney disease (DKD) in patients with type 2 diabetes mellitus (T2DM). Methods: A retrospective cohort study. The clinical data of 2 180 T2DM patients without DKD who underwent case management at Lee's United Clinic in Taiwan, China from 2002 to 2018 were retrospectively analyzed, including 1 103 females and 1 077 males, with an average age of (64.8±12.4) years. Regular follow-up was conducted for patients for at least 2 years, and their metabolic indexes were monitored annually. BMI variability independent of the mean (BMI-VIM), average yearly mean square successive difference (BMI-ASV), coefficient of variation (BMI-CV) and standard deviation (BMI-SD) were calculated,based on the body mass index (BMI) recorded annually by the patients. Patients were divided into four groups (Q1-Q4) based on the quartiles of the four weight variability indexes. DKD group and non-DKN group(NDKD group) were defined based on the occurrence of DKD at the end of the follow-up. Cox proportional hazards regression models were used to analyze the relationship between the four weight variability indicators and the incidence of DKD. Subgroup analysis was performed by categorizing patients into non-obesity (BMI<28 kg/m2) and obesity groups (BMI≥28 kg/m2) to investigate the impact of the four weight variability indicators on the risk of DKD. Results: After a follow-up of (4.55±2.13) years, 904 patients developed DKD. Compared with the NDKD group, patients in the DKD group had a higher proportion of females, older age, longer duration of diabetes, more insulin users, higher waist-to-hip ratio, higher levels of BMI-VIM, BMI-ASV, BMI-CV, BMI-SD, systolic blood pressure, diastolic blood pressure, and urine albumin-creatinine ratio, a lower proportion of hypoglycemic drugs, estimated glomerular filtration rate, and high-density lipoprotein cholesterol level, with statistically significant differences between the two groups(all P<0.05). Cox proportional hazards regression analysis results revealed that the risk of DKD in T2DM patients increased with the increase in BMI-SD, BMI-CV, BMI-VIM, and BMI-ASV after correcting a series of influencing factors. In the BMI-VIM subgroup, compared with the Q1 group, the risk of DKD in the Q4 group increased by 22.4% [HR=1.224 (95%CI:1.008-1.487), P=0.041]. In the BMI-ASV group, compared with the Q1 group, the risk of DKD in the Q4 group increased by 51.1% [HR=1.511 (95%CI:1.240-1.841), P<0.01]. In the BMI-CV group, compared with the Q1 group, the risk of DKD in the Q4 group increased by 22.2% [HR=1.222 (95%CI:1.006-1.485), P=0.044]. In the BMI-SD subgroup, compared with the Q1 group, the risk of DKD in the Q4 group increased by 22.2% [HR=1.222 (95%CI:1.002-1.490), P=0.048]. Sub-group analysis showed that when the non-obesity group was grouped by BMI-ASV, after correcting a series of influencing factors, compared with the Q1 group, the highest risk of DKD occurred in the Q4 group [HR=1.551 (95%CI:1.228-1.958), P<0.001];when the obesity group was grouped by BMI-ASV, after correcting a series of influencing factors, compared with the Q1 group, the highest risk of DKD occurred in the Q4 group [HR=1.703 (95%CI:1.168-2.485), P=0.006]. Conclusion: Increases in BMI-VIM, BMI-ASV, BMI-CV, and BMI-SD are associated with an increased risk of DKD in T2DM patients.

[A survey of performance of public health risk assessment in emergencies of institutions for disease control and prevention at different levels in China].

Objective: To understand the performance of public health risk assessment in emergencies of institutions for disease control and prevention at different levels in China, and provide suggestions for the improvement of public health risk assessment. Methods: A self-administered survey was conducted in professionals involved in public health risk assessment in emergencies from national institution, provincial institutions and some prefectural institutions for disease control and prevention (1-2 prefectural institutions were selected using convenience sampling in each province) between March and April in 2021. Results: A total of 79 institutions for disease control and prevention were investigated, including 1 national institution, 32 provincial institutions and 46 prefectural institutions. By April 2021, all the 79 institutions surveyed had conducted risk assessment of public health emergencies, in which 61 (77.2%) had established departments responsible for the public health risk assessment, i.e. emergency management office or communicable disease prevention and control office (section), and regular risk assessment mechanisms. The main sources of information for public health risk assessment were public health surveillance systems, including the National Notifiable Diseases Reporting System (100.0%) and Public Health Emergencies Management Information System (97.5%). Compared with the provincial institutions, the prefectural institutions were more likely to use specific disease surveillance systems (84.8% vs. 62.5%; χ2=5.09, P=0.024). The risk management recommendations made by 43 institutions for disease control and prevention (54.4%) after the risk assessment were accepted by the superior health administrative departments and used in epidemic prevention and control. Conclusions: Public health risk assessment in emergencies has been widely carried out by national, provincial and prefectural institutions for disease control and prevention in China. Specialized departments and mechanisms have been established, but the information sources are still confined to public health surveillance systems and the application of the risk assessment results still needs to be further improved.

[Normative wideband absorbance measures in children: a cross-sectional study].

Objective: This study was to investigate the main characteristics and related factors of wideband absorbance (WBA) in children with normal hearing and to obtain age-specific reference range of WBA. Methods: 384 children between 0-12 years old (615 ears) who visited the Beijing Children's Hospital, Capital Medical University from October 2019 to February 2021 were enrolled, including 230 males (376 ears) and 154 females (239 ears), with totally 306 left ears and 309 right ears. Wideband tympanometry (WBT) was performed and normative WBA data were analyzed by SPSS 24.0 statistical software. Repeated measures and multivariate analysis of variance were applied to the data from 16 points at 1/3-octave frequencies (226, 324, 408, 500, 667, 841, 1 000, 1 297, 1 682, 2 000, 2 670, 3 364, 4 000, 5 339, 6 727 and 8 000 Hz) to evaluate the effects of frequency, age, external auditory canal pressures, gender and ear on WBA. Results: According to the WBT frequency-absorbance curve, the subjects were divided into seven groups: 1-month old group, 2-month old group, 3-month old group, 4-5 month old group, 6-24 month old group,>2-6 year old group and>6-12 year old group. The WBA of normal-hearing children underwent a series of developmental changes with age at both ambient pressure and tympanometric peak pressures. WBA results for 1-month group and 2-month old group exhibited a multipeaked pattern, with the peaks occurring around 2 000 and 4 897 Hz, and a notch around 3 886 Hz. WBA results for 3-month group and 4-5 month old group exhibited a single broad-peaked pattern, with the peak occurring between 2 000-4 757 Hz. The WBA of 1-month old group to 4-5 month old group decreased gradually at low frequency (226-408 Hz) and 6 727 Hz, and increased at middle to high frequency (2 670-4 000 Hz). The WBA of 6-24 month old group were significantly lower than that of 2-month old group to 4-5 month old group at all frequencies except 3 364 and 4 000 Hz. WBA results for 6-24 month old group,>2-6 year old group and>6-12 year old group exhibited a single-peaked pattern, and the peak frequency of WBA moved to the lower frequency successively. From 6-24 month old group to>6-12 year old group, the WBA gradually increased at low to middle frequencies (667-2 670 Hz) and 8 000 Hz, and decreased at middle to high frequencies (3 364-5 339 Hz). Among the 16 frequencies of all age groups, the difference between WBA under ambient pressure and tympanometric peak pressure were -0.09-0.06, and 43.75%-81.25% frequency points had statistically significant difference, which was mainly manifested in that WBA under ambient pressure were lower than that under tympanometric peak pressure at 226-1 682 Hz. There was no significant ear effect on all of the age groups. Similarly, there was no significant gender effect except for 3-month old group and 4-5 month old group. Conclusions: The WBA of normal-hearing children measured at ambient pressure and tympanometric peak pressure varied across the frequencies with age from 1 month to 12 years old, and different frequencies followed different change patterns (increase vs. decrease) in WBA. There was also significant external auditory canal pressures effect on all of the age groups. The establishment of age-specific reference range of WBA for 0-12 years old normal-hearing children in this study would be useful for clinical practice of determining normative data regarding WBT.

[The prognostic value of free triiodothyronine/free thyroxine ratio in patients hospitalized with heart failure].

Objective: To investigate the effect of free triiodothyronine/free thyroxine (FT3/FT4) ratio on the prognosis of patients with heart failure (HF). Methods: A total of 3 527 patients hospitalized in the Heart Failure Center of Fuwai Hospital from March 2009 to June 2018 were analyzed in our study. Patients were divided into two groups according to median of FT3/FT4 ratio: low FT3/FT4 group (n=1 764, FT3/FT4<2.15) and high FT3/FT4 group (n=1 763, FT3/FT4≥2.15). The primary endpoint was defined as a composite endpoint of all-cause death or heart transplantation or implantation of a left ventricular assist device. The baseline characteristics of patients with different FT3/FT4 ratio groups were compared, and a multivariate Cox proportional hazard regression model was used to analyze the relationship between FT3/FT4 ratio and the prognosis of hospitalized patients with HF. Results: The age of the total population was (56.8±16.0) years, and 2 544 cases (72.1%) were males. The median follow-up time was 2.79 (1.00, 5.03) years, and a total of 1 542 end-point events were recorded at the final follow-up. The mean ages of patients in the low FT3/FT4 group and high FT3/FT4 group were (58.8±16.5) and (54.8±15.2) years (P<0.001), respectively; and the cumulative survival rates were 38.4% and 61.9%, respectively (P<0.001). FT3 (HR=0.72, 95%CI: 0.63-0.84, P<0.001), FT3/FT4 (HR=0.76, 95%CI: 0.65-0.87, P<0.001) was associated with all-cause death, heart transplantation, or LVAD implantation in patients with heart failure. HR values (95%CI) of FT3/FT4 ratio predicting the risk of composite endpoint in the subgroup of left ventricular ejection fraction (LVEF)<40%, 40% to 49%, and≥50% were 0.91 (0.77-1.08), 0.83 (0.50-1.39), and 0.65 (0.50-0.85), respectively (P interaction=0.045). Conclusions: Low FT3 and low FT3/FT4 are important correlative factors for poor prognosis in hospitalized HF patients, especially in patients with LVEF≥50%.

A critical evaluation of physical and manufacturing properties of genuine and counterfeit rotary nickel-titanium endodontic instruments.

BACKGROUND: Rotary nickel-titanium (NiTi) instruments are made to exacting standards and are costly to manufacture, and quality control is paramount. Consequently, unauthorized factories make counterfeit instruments that are less expensive and may therefore be attractive to dentists. Little information exists about the metallurgy and manufacturing quality of such instruments. There is the potential for counterfeit instruments to be at higher risk of fracture during treatment, thereby compromising clinical outcomes. The aim of this study was to evaluate physical and manufacturing properties of genuine and counterfeit ProTaper Next™ and Mtwo® rotary NiTi instruments. METHODS: This study investigated the metallurgical properties, manufacturing quality, microhardness and number of cycles to failure of two commonly used rotary NiTi systems and compared them with counterfeit products purporting to be genuine articles. RESULTS: Counterfeit instruments were found to be inferior in manufacturing standards and were less resistant to cyclic fatigue when compared to genuine instruments. CONCLUSIONS: Counterfeit rotary NiTi instruments may be less efficient at preparing root canals and may be at higher risk of fracture during endodontic treatment. Dentists must be aware that, although less expensive, counterfeit instruments may be of dubious manufacturing quality and at higher risk of fracture if used in patients. © 2023 Australian Dental Association.

[Yang Shoushan Medical Cases in the Wumen Medical School].

The unique manuscript, Yang Shoushan Medical Cases, is now held by the library of Nanjing University of Chinese Medicine.It is the medical cases collection of Yang Shoushan, a well-known doctor of Suzhou in the late Qing Dynasty.It was found that the number of medical cases and the details of each case recorded in this book were much more than that in his other existing medical writings. It greatly enriches the historical materials for the study of Yang's clinical characteristics and academic thought.Its compiler was Huang Shounan, a physician and calligrapher in Suzhou in the late Qing Dynasty and the early Republic of China.This book was not recorded as a book compiled by Huang Shounan before now. This book was believed to be completed in 1890.

[Clinical features and prognosis of patients hospitalized with heart failure and low T3 syndrome].

Objective: To investigate the association between triiodothyronine (T3) and inflammatory factors, and its potential effect on long-term outcomes in hospitalized patients with heart failure (HF). Methods: A total of 2 475 patients with HF admitted in Heart Failure Care Unit were consecutively enrolled in this retrospective cohort study from December 2006 to June 2018. Patients were divided into low T3 syndrome group (n=610, 24.6%) and normal thyroid function group (n=1 865, 75.4%). The median follow-up time was 2.9 (1.0, 5.0) years. A total of 1 048 all-cause deaths were recorded at the final follow-up. The effects of free T3 (FT3) and high-sensitivity C-reactive protein (hsCRP) on the risk of all-cause death were evaluated by Cox regression analysis and Kaplan-Meier analysis. Results: The age of the total population was 19-95 (57±16) years, 1 823 cases (73.7%) were male. Compared to those with normal thyroid function, albumin [(36.5±5.4) vs. (40.7±4.7) g/L], hemoglobin [(129.4±25.1) vs. (140.6±20.6) g/L], total cholesterol [3.6 (3.0, 4.4) vs. 4.2 (3.5, 4.9) mmol/L] (all P<0.001) were lower, Whereas age [(60.5±16.0) vs. (55.2±15.4) years], creatinine [105.0 (83.6, 137.0) vs. 87.8 (75.6, 106.3) mmol/L], log N-terminal B-type natriuretic peptide [(8.2±1.3) vs. (7.2±1.4) ng/L] were higher in LT3S patients (all P<0.001). In Kaplan-Meier survival analysis, patients with lower FT3 and higher hsCRP had significantly lower cumulative survival (P<0.001), lower FT3 combined with higher hsCRP subgroup had the highest risk of all-cause death (Ptrend<0.001). In multivariate Cox regression analysis, LT3S was an independent predictor of all-cause mortality (HR=1.40, 95%CI 1.16-1.69, P<0.001). Conclusion: LT3S is an independent predictor of poor prognosis in patients with heart failure. FT3 combined with hsCRP improve the predictive value of all-cause death in hospitalized patients with heart failure.

[Imaging observation and analysis of condylar osteosclerosis in temporomandibular joint osteoarthrosis].

Objective: To observe the different imaging manifestations of condylar sclerosis in temporomandibular joint osteoarthrosis and explore the imaging significance of condylar sclerosis. Methods: From January 2018 to December 2020, 50 patients with temporomandibular joint condylar sclerosis were examined by cone-beam CT (CBCT) and underwent spiral CT, MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA. There were 15 males and 35 females aged from 16 to 65 years with age of (42.7±14.5) years. The imaging manifestations of CBCT, spiral CT, MRI and radionuclide bone imaging, joint disc displacement and abnormal bone metabolism of condylar sclerosis were analyzed. And the area of condylar sclerosis was graded according to the image of CBCT. Results: A total of 50 patients were included, including 38 unilateral condylar sclerosis, 12 patients with bilateral condylar sclerosis, the total condylar sclerosis were 66. There was no significant difference between the detection rate of further spiral CT (95.5%, 63/66) and CBCT (100.0%, 66/66) (corrected χ²=1.36,P=0.244). The area of condylar sclerosis was (35.5±4.5) mm2, ranged from 1 to 100 mm2. In addition, spiral CT showed more clearly condylar sclerosis than CBCT. Sclerosis can occur in all parts of condyle, mainly in the upper middle region (68.2%,45/66) in coronal position and in the upper front region (71.2%,47/66) in sagittal position. Fifty-seven condylar sclerosis were detected by MRI, including 4(4/19) condylar sclerosis less than 4 mm2. There was significant difference in the displacement of temporomandibular joint disc between the sclerotic side and the non sclerotic side (χ²=10.09, P=0.006). MRI display the condylar sclerosis showed low signal (56/62), followed by high signal (5/62) and medium signal (1/62). Radionuclide bone imaging showed that 4 of the 38 patients with unilateral condyle sclerosis had symmetrical bone metabolism, 34 had abnormal bone metabolism, and 21 patients had concentrated on the non-sclerotic side. Radionuclide bone imaging showed that 4 of the 38 patients with unilateral condyle sclerosis had symmetrical bone metabolism and 34 had abnormal bone metabolism. Conclusions: Spiral CT is more accurate than CBCT in terms of condyle sclerosis through different imaging analysis, and the detection rate of both is higher than MRI. Most of condylar sclerosis showed different degrees of low signal on MRI. The condylar sclerosis side is usually manifested by abnormal bone metabolism.

[Effect of low density carotid plaque on the development of cerebral small vessel disease in patients with carotid stenosis].

Objective: To investigate the correlation between cerebral small vessel disease (CSVD) and carotid low-density plaque on multi-slice spiral CT angiography (MSCTA) in patient with carotid stenosis. Methods: The clinical data of 221 patients with carotid stenosis who admitted to Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, from January 2016 to January 2021 were retrospectively analyzed. There were 195 males and 26 females, with the age of (70.0±8.4) years (range: 48 to 88 years). According to MRI, the patients were divided into carotid stenosis combined with CSVD group (the CSVD group) and carotid stenosis without CSVD group (the non-CSVD group). Lowest density in the carotid atherosclerotic plaque area (CAPALD) was analyzed by MSCTA. The t-test, Mann-Whitney U test and Chi-square test were used for comparison between the two groups. Univariate and multivariate Logistic regression analysis were performed on CAPALD and other clinical indicators with CSVD. Receiver operating characteristic (ROC) curves of CAPALD and CAPALD combined with the demographics (sex, age and body mass index) were plotted for predicting CSVD, and the area under the curve (AUC), sensitivity and specificity were calculated. Results: There were 169 patients in the CSVD group and 52 patients in the non-CSVD group. In the CSVD group, 88.8% (150/169) were males and 11.2% (19/169) were females, with the age of (70.5±8.2) years (range: 48 to 88 years). In the non-CSVD group, 86.5% (45/52) were males and 13.5% (7/52) were females, with the age of (68.4±9.1) years (range: 51 to 85 years). CAPALD and the score of Montreal cognitive assessment were lower in the CSVD group than those in the non-CSVD group (21.0 HU vs. 35.0 HU, Z=-3.760, P<0.01; 22.6±3.9 vs. 24.8±3.3, t=-2.064, P<0.05). Multivariate Logistic regression analysis showed that CAPALD was an independent factor for CSVD (OR=1.044, 95%CI:1.020 to 1.070, P<0.01). The AUC of the ROC curve for CAPALD predicting carotid stenosis with CSVD was 0.672 (P<0.01), with cut-off value of 34.5 HU, sensitivity of 82.8%, and specificity of 50.0%. The AUC of ROC curve for CAPALD combined with the demographics predicting CSVD was 0.733 (P<0.01), with sensitivity of 82.9% and specificity of 64.0%. Conclusions: The decreased CAPALD is a risk factor for CSVD in patients with carotid stenosis. The analysis of carotid plaque density by MSCTA may help to identify the patients at high risk of CSVD.

[A prospective cohort study on refractive status of schoolchildren in Huangzhong District, Xining City, Qinghai Province].

Objective: To determine the characteristics and progress of the visual acuity and refractive state of schoolchildren in Huangzhong District, Xining City, Qinghai Province in China. Methods: Cohort study. Department of Ophthalmology, Beijing Children's Hospital carried out a cohort study by collecting the visual acuity and refractive state of Grade 1-5 schoolchildren among 16 primary schools in Huangzhong District, Xining City, Qinghai Province in September 2020 and July 2021. Cycloplegic retinoscopy with eye drop which contained tropicamide (0.5%) and phenylephrine hydrochloride (0.5%) was performed in children with low vision(<1.0). Myopia was defined as the spherical equivalent (SE) ≤-0.5 D after cycloplegic retinoscopy. Measurement data was analyzed by t-test and enumeration data was analyzed by χ2 test. Multiple linear regression was used to analyze the influencing factors. Results: The 2 489 individuals with repeated tests in two years were included in the follow-up study, among whom the prevalence of myopia was 26.24%(653/2 489) in 2020, while 32.94% (820/2 489)respectively in 2021. The incidence of myopia in one school year from grades 1 to 5 was 11.19%(47/420), 5.44%(21/386), 6.39%(25/391), 11.52%(44/382) and 11.67%(30/257). The average SE of children in all grades in 2021 increased negatively from the previous year (Grade 1 to Grade 5 increased respectively: 0.40 D, 0.69 D, 0.62 D, 0.52 D and 0.37 D). Conclusions: The prevalence of myopia among schoolchildren in Huangzhong District, Xining City, Qinghai Province was relatively high. There were two peaks of myopia incidence in the first, fourth and fifth grades. Female, age, and the baseline of SE were the related influencing factors for myopia progression.

[Complications related to axial orientation of implants and their research progress].

The ideal axial orientation of implant is the key to the success of implant denture restoration. According to the restoration-oriented concept of implant, the implant axis direction should be consistent with the long axis direction of the suprastructure. In clinical practice, implant axial deviation leads to related complications, such as implant fracture, periimplant inflammation, and poor esthetic outcome of implant restoration, resulting in implant treatment failure. In this paper, complications related to improper implant axial orientation, their causes and treatment strategies are reviewed.

Influence of light supplement on duck sternal calcification from integrated analysis of metabolome and transcriptome.

Calcification of bones is the critical process of bone development in birds, which is very important for sustaining the normal biological function of bones. Light is one of the vital factors affecting bone development, but whether light intensity affects bone calcification and the underlying mechanism is still unknown. In this study, we used duck sternum as a model to analyze the calcification process under different light regimes. In addition, the underlying mechanism was also illustrated by integrating metabolomics and transcriptome methods. The experiment lasted from 14 to 51 d of duck age. The control group (LP1) kept light intensity 2 lx during the whole experiment. The two light supplement groups (LP2, LP3) were given light with the intensity of 70 lx at different time (14-29 d for LP2, 14-43 d for LP3). Samples were collected at 52 d of duck age. Sternal calcification analysis showed no significant difference in proportion of area of cartilage matrix and trabecular bone in keel tissue among the 3 groups, but the degree of keel calcification in LP3 was higher than in the other 2 groups. Serum metabolomics showed 32 and 28 differentially accumulated metabolites (DAMs) in the 2 comparison groups, LP1 vs. LP3 and LP1 vs. LP2, respectively. Carboxylic acids and derivatives were the most abundant among the DAMs. Sternal transcriptome analysis showed 231 differentially expressed genes (DEGs), including 177 upregulated genes and 54 downregulated genes in group LP1 vs. LP3, and 22 DEGs in group LP1 vs. LP2. Protein-protein interaction (PPI) network analysis on DEGs between LP1 and LP3 showed that genes BTRC, GLI1, BMP4, and FOS were in the core position of the interaction network, and are also involved in bone development. KEGG pathway analysis of DAMs and DEGs showed that differences in Hedgehog signaling pathway, MAPK signaling pathway, apoptosis, energy metabolism, and amino acid metabolism following light treatment seem likely to have contributed to the observed difference in calcification of duck sternum.

[Multimodal imaging analysis of the cyst like lesion of condyle in temporomandibular joint].

Objective: To investigate the imaging features of condylar cystic degeneration of temporomandibular joint (TMJ) by cone-beam CT (CBCT), spiral CT, MRI and radionuclide bone imaging. Methods: From January 2018 to December 2020, thirty-two patients with cyst-like lesions of condylein temporomandibular joint were examined by CBCT, spiral CT, MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA. There were 12 males and 20 females involved, aged from 16 to 65 years with an average age of (33.9±12.5) years. The characteristics of CBCT, spiral CT, MRI and radionuclide bone imaging were analyzed. Condylar cyst like lesions were classified as type A and type B based on the presence or absence of surface bone defects. Condylar cyst like lesions were classified as type Ⅰ(yes) and type Ⅱ(no) according to the accompanying bone marrow edema-like lesions of the condyles. The incidence of condylar bone marrow edema, disc displacement and abnormal bone metabolism were analyzed. Results: A total of 64 joint images of 32 patients were included, including 34 sides with TMJ cyst-like lesion and 6 sides with multiple cyst-like lesions,the total cyst-like lesions were 42. The largest diameter of cyst-like lesion ranged from 1.0 to 12.4 mm, with an average length of (3.7±1.8) mm. There were 24 cases of type A TMJ cyst like lesion and 10 cases of type B cyst-like lesion. The detection rate of CBCT was 95.2% (40/42) and that of spiral CT was 100% (42/42), there was no significant difference (Calibration Chi-square=0.51, P=0.474). The detection rate of nuclear magnetic resonance was 80.1% (34/42), and the detection rate of cyst-like lesions less than 2 mm was 3/11. In the cyst like lesion side, there were 9 sides with anterior disc displacement with reduction, 20 sides with anterior disc displacement without reduction. In the non-cyst like lesion side, 10 sides with anterior disc displacement with reduction and 6 sides with anterior disc displacement without reduction. There was a significant difference in the displacement of the disc between cyst-like and non-cystic lesion side (χ²=7.80, P=0.005). MRI showed that 6 cases of cystic side[17.6% (6/34)] had bone marrow edema-like lesions (all type A), 1 case of non-cyst like lesions side [3.3% (1/30)]had bone marrow edema-like lesion, there was no significant difference between cystic and non-cystic lesions (Calibration Chi-square=2.04, P=0.153). There was a significant difference between type A and B cystic lesions (Fisher exact probability method, P= 0.024). Radionuclide bone imaging showed abnormal bone metabolism in 26 patients in the cyst-like lesion side and 5 patients in the non-cyst like lesion side (χ²=22.82, P<0.001). Conclusions Multi-slice Spiral CT could detect the cyst-like lesion of TMJ condyle in the early stage, which is different from the large joint. And the formation mechanism may vary from the different classifications.

[Multimodal imaging analysis of the cyst like lesion of condyle in temporomandibular joint].

Objective: To investigate the imaging features of condylar cystic degeneration of temporomandibular joint (TMJ) by cone-beam CT (CBCT), spiral CT, MRI and radionuclide bone imaging. Methods: From January 2018 to December 2020, thirty-two patients with cyst-like lesions of condylein temporomandibular joint were examined by CBCT, spiral CT, MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA. There were 12 males and 20 females involved, aged from 16 to 65 years with an average age of (33.9±12.5) years. The characteristics of CBCT, spiral CT, MRI and radionuclide bone imaging were analyzed. Condylar cyst like lesions were classified as type A and type B based on the presence or absence of surface bone defects. Condylar cyst like lesions were classified as type Ⅰ(yes) and type Ⅱ(no) according to the accompanying bone marrow edema-like lesions of the condyles. The incidence of condylar bone marrow edema, disc displacement and abnormal bone metabolism were analyzed. Results: A total of 64 joint images of 32 patients were included, including 34 sides with TMJ cyst-like lesion and 6 sides with multiple cyst-like lesions,the total cyst-like lesions were 42. The largest diameter of cyst-like lesion ranged from 1.0 to 12.4 mm, with an average length of (3.7± 1.8) mm. There were 24 cases of type A TMJ cyst like lesion and 10 cases of type B cyst-like lesion. The detection rate of CBCT was 95.2% (40/42) and that of spiral CT was 100% (42/42), there was no significant difference (Calibration Chi-square=0.51, P=0.474). The detection rate of nuclear magnetic resonance was 80.1% (34/42), and the detection rate of cyst-like lesions less than 2 mm was 3/11. In the cyst like lesion side, there were 9 sides with anterior disc displacement with reduction, 20 sides with anterior disc displacement without reduction. In the non-cyst like lesion side, 10 sides with anterior disc displacement with reduction and 6 sides with anterior disc displacement without reduction. There was a significant difference in the displacement of the disc between cyst-like and non-cystic lesion side (χ²=7.80, P=0.005). MRI showed that 6 cases of cystic side[17.6% (6/34)] had bone marrow edema-like lesions (all type A), 1 case of non-cyst like lesions side [3.3% (1/30)] had bone marrow edema-like lesion, there was no significant difference between cystic and non-cystic lesions (Calibration Chi-square=2.04, P=0.153). There was a significant difference between type A and B cystic lesions (Fisher exact probability method, P=0.024). Radionuclide bone imaging showed abnormal bone metabolism in 26 patients in the cyst-like lesion side and 5 patients in the non-cyst like lesion side (χ²=22.82, P<0.001). Conclusions Multi-slice Spiral CT could detect the cyst-like lesion of TMJ condyle in the early stage, which is different from the large joint. And the formation mechanism may vary from the different classifications.

[Research progress of dental pulp stem cells for peripheral nerve injury repair].

Peripheral nerve injuries are mainly related to severe trauma, fracture and tumor surgery, leading to reduced quality of life and impaired physical and mental health. The repair of peripheral nerve still faces great challenges in clinic, and the research on the regeneration and repair of peripheral nerve has become a hot issue in related disciplines. Cell therapy plays an irreplaceable role in tissue regeneration and repair. Schwann cells are ideal cells for peripheral nerve repair, but their limited sources inhibit the clinical application. Dental pulp stem cells are derived from neural crest, which provides a new cell source for nerve regeneration. The purpose of this article is to review the research progress of dental pulp stem cells for peripheral nerve repair.

[Investigation of contamination of SARS-CoV-2 in imported frozen seafood from a foreign cargo ship and risk factors for infection in stevedores in Qingdao].

Objective: To investigate the contamination status of SARS-CoV-2 in imported frozen seafood from a Russia cargo ship in Qingdao and to analyze the risk factors for infection in local stevedores. Methods: The method of "two-stage, full coverage and mixed sampling" was used to collect the seafood packaging samples for the nucleic acid detection of SARS-CoV-2 by real-time fluorescent quantitative RT-PCR. A unified questionnaire was designed to investigate 71 stevedores in two shifts through telephone interview. The stevedores were divided into two groups, with 23 in the shit with two infections was group A and 48 in the shift without infection was group B. Software Epi Info7.2 was used to identify the risk factors for SARS-CoV-2 infections in the stevedores. Results: In the frozen seafood from a Russia cargo ship, the total positive rate of SARS-CoV-2 nucleic acid in the frozen seafood was 11.53% (106/919). The positive rate of SARS-CoV-2 nucleic acid in the frozen seafood unloaded by group A (14.29%,70/490) was significantly higher than that in the frozen seafood unloaded by group B (8.39%,36/429)(χ2=7.79,P=0.01) and the viral loads detected in the frozen seafood unloaded by group A were higher than those detected in the frozen seafood unloaded by group B. The scores of personal protection and behaviors in the stevedores in group A were significantly lower than those in group B (P<0.05), and toilet use, smoking and improper hand washing before meals were the risk factors for the infection. Conclusions: The imported frozen seafood was contaminated by SARS-CoV-2 and the contamination distribution was uneven. Supervision and management of personal occupational protection and behaviors of workers engaged in imported frozen food transportation should be strengthened. It is suggested that a closed-loop monitoring and management system for the whole process of "fishing-transport- loading/unloading" should be established by marine fishery authority.

[Design and application of three-dimensional printing guide plate for oral and maxillofacial surgery].

Objective: To explore the application of three-dimensional (3D) printing technology in oral and maxillofacial surgery, so as to optimize and standardize its design and application. Methods: From January 2010 to December 2020, 40 cases of mandibular tumor surgery (20 cases of conventional group and 20 cases of guide plate group), 20 cases of temporomandibular joint replacement surgery (10 cases of conventional group and 10 cases of guide plate group), 20 cases of malocclusion surgery (10 cases of conventional group and 10 cases of guide plate group), 20 cases of radioactive particle implantation surgery (10 cases of CT guided group and 10 cases of guide plate group) were analyzed. All patients in the guide plate group were scanned with spiral CT, and the 3D models of the jaw and the donor bone area were reconstruction. According to the purpose of surgical guide, the design and clinical application of osteotomy guide, in place forming guide and puncture positioning guide were analyzed respectively. The design time of guide plate, the performance and printing time of guide material, the sterilization method of guide and its influence on accuracy, and the influence of guide application on operation time and accuracy were analyzed. Results: The design time of orthognathic guide plate was (2.9±1.8) d, and the design time of mandibular transplantation guide plate was (2.8±1.8) d, that of the temporomandibular joint replacement guide plate and the puncture guide plate was (2.2±0.3) and (0.9±0.3) d. The average printing time of the 40 maxilla model was (11.1±1.6) h, and that of the 40 mandible models was (2.6±0.4) h. The average printing time of the 40 sets of osteotomy and positioning guide plate was (2.5±0.8) h, and that of the 10 puncture positioning guide plate (1.1±0.4) h. The operation time of the conventional group was (6.99±1.10) and (6.02±0.55) h. In the CT guided group, the operation time was (1.91±0.55) h and (0.89±0.15). The operation time of mandible tumor operation and radioactive particle implantation in the guide plate group was less than that in the control group (P<0.05), and there was no significant difference in the operation time of orthognathic surgery and joint replacement between the two groups (P>0.05). The displacement distance of the mark points in the TMJ replacement and mandibular tumor operation guide group was less than that in the control group (P<0.05), and the error of the guide plate in orthognathic operation and particle implantation operation was basically less than 1 mm. Conclusions: The application of the surgical guide plate made by 3D printing technology helps to complete the operation more safely, accurately and quickly, But its design, manufacture and disinfection still need to be further standardized and improved.