[Investigation of serum surface active protein D and clara cell protein levels in workers exposed to silica dust in ferrous metal foundry].

Objective: To investigate the levels of serum surface active protein D (SP-D) and clara cell protein (CCl6) in workers exposed to black silica dust, and analyze its influencing factors. Methods: From July to September 2021, 174 workers in 37 positions exposed to silica dust in 5 ferrous metal foundry were investigated by cross-sectional research method. The exposure concentration of silica dust workers was obtained through occupational health field investigation and detection, and the general situation of the study subjects was obtained through questionnaire survey and peripheral blood was collected. Double antigen sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of SP-D and CC16 in serum of workers. The mean values were compared by one-way ANOVA, and the influencing factors of SP-D and CC16 concentrations in serum were analyzed by ordered multiple logistic regression. Results: The time-weighted average concentration (C-TWA) of 174 workers exposed to silica dust (respirable dust) ranged from 0.09 mg/m(3)~3.58 mg/m(3), and the C-TWA overstandard rate of dust exposed workers was 32.18% (56/174) , with differences among workers in different positions (χ(2)=28.85, P<0.001) . The highest concentration of silica dust was (0.82±0.11) mg/m(3). Using C-TWA<50% OEL occupational exposure limit (OEL) as reference, serum SP-D concentration in workers with ≥50% OEL was increased (OR=4.95, 95%CI: 1.86~13.17, P=0.001) , while CC16 concentration was decreased (OR=0.15, 95%CI: 0.05~0.40, P<0.001) ; Serum CC16 concentration decreased in workers exposed to silica dust C-TWA≥OEL (OR=0.46, 95%CI: 0.28~0.98, P=0.043) . Compared with those with low occupational health literacy, the serum SP-D concentration of workers with high occupational health literacy decreased (OR=0.48, 95%CI: 0.25~0.92, P=0.027) and CC16 concentration increased (OR=2.09, 95%CI: 1.10-3.97, P=0.024) . Conclusion: When no abnormality was found in the physical examination of workers, the serum SP-D and CC16 concentration levels changed, and the change was related to the concentration of workers exposed to silica dust.

[Analysis of dust hazard characteristics in 59 ferrous metal foundry enterprises in Ningbo City].

Objective: To analyze the post distribution of dust concentration in ferrous metal foundry enterprises and evaluate the occupational health risks, and provide basis for policies of the formulation of pneumoconiosis prevention and control. Methods: From August to September in 2020, the basic information, dust hazard information and occupational health management information of 59 ferrous metal casting enterprises were investigated, the dust concentration distribution was analyzed, and the risk assessment was carried out by using the quantitative assignment model. The dust concentration is tested by LSD method after logarithmic treatment. The 3 times time weighted average allowable exposure concentration of dust is taken as the peak concentration limit of dust; The time weighted average allowable exposure concentration of dust converted by exposure time is taken as the time weighted average exposure concentration limit of dust, and whether the time weighted average exposure concentration and peak concentration of dust at the same post exceed the limit is taken as the basis for exceeding the limit of dust post concentration to calculate the post exceeding the limit rate. Results: The dust hazards were mainly distributed in the posts of sand treatment, molding, sand falling, sand cleaning and cutting and grinding. Dust exposure time weighted average concentration was 0.44 (0.03, 5.11) mg/m(3), peak exposure concentration was 1.30 (0.18, 10.94) mg/m(3), and the over standard rate of Posts was 38.92% (79/203) . Weighted average exposure concentration of other dust (total dust) in the cutting and grinding post is 1.50 (0.15, 7.40) mg/m(3), peak exposure concentration is 0.90 (0.07, 12.48) mg/m(3), and the post exceedance rate is 4.88% (2/41) . Weighted average exposure concentration of silica dust (exhaling dust) in dust operation posts of investment casting enterprises is 0.43 (0.05, 6.35) mg/m(3), peak exposure concentration is 0.90 (0.12, 8.28) mg/m(3), and the post over standard rate is 35.77% (49/137) ; Weighted average exposure concentration of other dust (total dust) at the cutting and grinding post is 2.00 (11.00, 21.00) mg/m(3), and the post exceedance rate is 2.50% (2/80) . There was no significant difference in the concentration of respirable dust between sand casting and investment casting (P>0.05) . The concentration of respirable dust in sand casting was higher than that in sand treatment, molding and sand cleaning posts (P<0.05) . The concentration of silica dust in investment casting was higher than that in sand treatment and molding posts, and that in sand cleaning posts was higher than that in sand treatment posts (P<0.05) . 98.48% (454/461) of the dust operation posts have an occupational health risk value greater than or equal to 400, and 1.52% (7/461) of the dust operation posts have an occupational health risk value of 200~399. Conclusion: there is a high rate of exceeding the standard in the dust work posts in the ferrous metal foundry enterprises in Ningbo, and the workers have a high occupational health risk of pneumoconiosis or metal and its compound pneumoconiosis. Targeted measures should be taken to reduce the occupational health risk.

[Current status and projection of non-communicable diseases in 126 countries participating in the Belt and Road initiative].

Objective: To compare the indicators of non-communicable diseases (NCD) and predict the achieving time of United Nations (UN) Sustainable Development Goals (SDG) in 125 countries participating in the Belt and Road (B&R) initiative and China. Methods: Using the open access data of Global Burden of Disease study, we first got the premature mortality rates of four main chronic diseases (cardiovascular disease, cancer, diabetes and chronic respiratory diseases) and suicide mortality rate in the 126 countries from1990 to 2017. We transformed the value of each indicator into a scale of 0-100 in percentile for each country and applied geometric mean to calculate total NCD score for comparison among 126 countries. We then examined the association of NCD scores with socio-demographic index (SDI) values. Finally, we used annualized rates of change during 1990-2015 to predict achieving time of the UN goal by 2030 for each indicator of chronic diseases premature mortality rate and suicide mortality rates in each B&R country. Results: The integral median of total NCD score in the 126 countries in 2017 was 82.7. The score of China was 87.6, ranking 33(rd). The top three countries were Kuwait (98.1), Peru (97.5) and Italy (96.0). The last three countries were Papua New Guinea (28.9), Vanuatu (54.7) and Ukraine (58.0). The total NCD score showed positive correlation with SDI values (r=0.33) mainly due to chronic disease indicator (r=0.45). Fifteen countries will achieve the SDG goal of chronic disease premature mortality in or before 2030, but China will achieve it in 2038. Fifteen countries are expected to achieve the goal of suicide mortality, and China will acheive the goal ahead of schedule in 2024. Conclusions: The NCD rates varied widely among the countries along B&R. It is a challenge to achieve the SDG goal of chronic disease premature mortality rate by 2030 for China. In order to achieve the SDG goals by 2030, we should strengthen multilateral cooperation and complement each other's advantages, and reduce NCD mortality of people and improve people's health in countries along B&R.

[Observation of oral Streptococcus oligofermentans colonization in rats].

OBJECTIVE: To study the colonization ability of Streptococcus oligofermentans (S. oligofermentan) in the condition of high sucrose in oral cavity of rats. METHODS: In this study, 48 SPF-SD rats aged 21 days were selected. From 24th to 27th days, the rats were fed with water of antibiotic and fed with high glucose diet continuously. On the 28th day, the rats were divided into four groups randomly, 12 rats per group. From the 28th day to 30th day, the first group (SM group) was inoculated with S. mutans, the second group (SO group) with S. oligofermentan, the third group (SO+SM group) with mixture of S. mutans and S. oligofermentan, the control group not with any bacteria. On the next day and the 10th day after inoculation of bacteria, the samples of dental plaque of the rats were acquired by scrubbing occlusal, buccal and lingual surfaces of bilateral mandibular molars with sterile swabs. The samples of SM group were inoculated on MSB and BHIS, of SO group on MSAE, of SO+SM group on MSB, MSAE and BHIS,of the control group on MSB and MSAE. S. mutans were screened and calculated on MSB, the suspected colonies of S. oligofermentan were screened and identified by the analysis of 16S rDNA. RESULTS: On the next day, the detection rate of S. oligofermentan was 33.3% (4/12) in the group of SO; in the group of SO+SM, the detection rate of S. oligofermentan was 0, the detection rate of S. mutans 100.00%, and the proportion of S. mutans 14.70%±4.53%; in the group of SM, the detection rate of S. mutans was 100.00%, the proportion of S. mutans 12.42%±4.27%. On the 10th day, in the group of SO, the detection rate of S. oligofermentan was 0; in the group of SO+SM, the detection rate of S. oligofermentan was 0, the detection rate of S. mutans 100.00%, and the proportion of S. mutans 15.78%±5.10%; in the group of SM, the detection rate of S. mutans was 100.00%,and the proportion of S. mutans 17.08%±5.75%. CONCLUSION: In the condition of the experiment where high glucose was maintained in the oral cavity in rats, S. oligofermentan appeared transiently and couldn't colonize in the rats.

Osteoclast Deficiency Contributes to Temporomandibular Joint Ankylosed Bone Mass Formation.

Ankylosed bone mass in temporomandibular joint ankylosis (TMJA) is an important factor affecting mouth-opening limitation. However, the mechanism underlying the occurrence of ankylosed bone mass remains unknown. Research has shown that osteoblasts and osteoclasts maintain balance in bone remodeling. Thus, we hypothesized that aberrant osteoclastogenesis and osteogenesis may be involved in the occurrence of ankylosed bone mass in TMJA. In this study, we characterized the osteogenesis of bone marrow stem cells and the osteoclastogenesis of myelomonocyte in clinical specimens of TMJA and normal controls. Results showed that, compared with control bone marrow stem cells, TMJA bone marrow stem cells had lower proliferative and osteogenic capacities. The number of osteoclasts in the ankylosed bone mass group dramatically decreased, and myelomonocyte osteoclastogenic potential was impaired. The RANKL/OPG ratio of the ankylosed bone mass group was lower than that of the control group. Thus, our study suggests that osteoclast deficiency may be an important factor affecting bone mass ankylosis.

Decreased osteogenesis in stromal cells from radiolucent zone of human TMJ ankylosis.

We previously hypothesized that the development of traumatic temporomandibular joint (TMJ) ankylosis was similar to that of hypertrophic non-union. Besides similarities in etiology, hypertrophic bone stumps, and long-term development, the radiolucent zone, frequently located in the ankylosed bone, is another common feature. In this study, we demonstrated that the radiolucent zone also contained multilineage potential cells (RZs, radiolucent-zone-related cells) as the non-union tissues. RZs were characterized and compared with mandibular bone marrow stem cells (BMSCs) by analysis of MSC-related markers, colony-forming-unit assays, multipotential differentiation assays, alkaline phosphatase (ALP) activity assays, and cell transplantation in vivo. Both cell types were positive for CD105, CD166, and Stro-1 expression, negative for CD34 and CD45 expression, and exhibited osteogenic, adipogenic, and chondrogenic differentiation potentials. However, compared with mandibular BMSCs, RZs showed lower colony-forming-unit abilities and proliferation rates. The mineralization and bone-forming ability of RZs was weaker than that of mandibular BMSCs, with Runx2 and ALP mRNA expression and ALP activity significantly lower in RZs. All these results suggest that RZs possess the properties of MSCs but lower proliferation and osteogenic differentiation capacity similar to that of stromal cells in hypertrophic non-union tissues.

A clinical investigation on disc displacement in sagittal fracture of the mandibular condyle and its association with TMJ ankylosis development.

This retrospective study evaluated the potential influence of the sagittal fracture pattern and articular disc displacement on the development of temporomandibular joint (TMJ) ankylosis. 33 sagittal fractures of mandibular condyles (SFMCs) in 19 patients were treated conservatively and were divided into non-ankylosis and ankylosis groups based on their prognosis. Using computed tomography (CT) images, the SFMCs were classified into types I, II and III, and the displacement of the articular disc was investigated using magnetic resonance imaging (MRI). There were 19 (58%) SFMCs in the non-ankylosis group: 5 were type I SFMCs, which did not show any disc displacement; the other 14 were type II SFMCs, which included 5 cases without disc displacement and 9 cases with disc displacement. In the non-ankylosis group, the lateral poles were completely or incompletely covered by the discs. There were 14 (42%) SFMCs in the ankylosis group, all of which were type III SFMCs showing disc displacement, and the lateral poles in these cases were not covered by the discs. This investigation confirmed that the disc position was highly associated with the position of the fractured fragment and that some SFMC patterns, especially type III SFMCs, indicated a high risk of TMJ ankylosis.

Does the presence of mandibular third molars increase the risk of angle fracture and simultaneously decrease the risk of condylar fracture?

Previous studies have shown that impacted mandibular third molars (M3s) increase the risk of mandibular angle fractures and decrease the risk of mandibular condylar fractures. This study attempted to verify these relationships and identify the influence of mechanism and cause of injury. The incidence of fractures was compared in 700 patients with and without impacted M3s. The results showed that patients with impacted M3s had a lower risk of condylar fracture and a higher risk of angle fracture than those without impacted M3s when injured by moderate trauma force. Such relationships could not have been identified when patients were injured by high trauma force. Patients with impacted M3s had a higher risk of angle fracture than those without impacted M3s no matter how they were injured (assault, fall, motor vehicle accident, other). When patients were injured by assault or in a motor vehicle accident, those with impacted M3s were less likely to have a condylar fracture. M3s were a dominant factor for developing a mandibular angle fracture and preventing condylar fracture. The risk of angle fracture was much more affected by impacted M3s than that of condylar fracture, when injury mechanism and cause were taken into consideration.