[Health hazards and hearing loss risk assessment of workers exposed to noise in an automobile manufacturing enterprise].

Objective: To investigate the current situation of occupational exposure to noise among noise workers in an automobile manufacturing enterprise in Tianjin, understand the impact of noise on workers＇ nervous system and hearing, and assess the risk of hearing loss among noise workers. Methods: In May 2021, 3516 workers in an automobile manufacturing enterprise were investigated by using a self-made questionnaire＂Noise Workers Questionnaire＂ and cluster sampling method. The occupational noise hygiene survey and occupational hazards detection were carried out in their workplaces. They were divided into noise exposure group and non-noise exposure group according to whether they were exposed to noise or not. The general characteristics, hearing and nervous system symptoms of the two groups of workers were compared, and the risk of hearing loss was assessed. Results: There were 758 workers in the noise exposure group, aged (26±5) years old, with a working age of 3.0 (2.0, 6.0) years exposed to noise. 2758 workers in the non-noise exposure group, aged (25±6) years old, with a working age of 2.0 (1.0, 4.0) years. There were statistically significant differences in the distribution of workers＇education level, working age and memory loss between the two groups (χ(2)=37.98, 38.70, 5.20, P<0.05). The workers in the noise exposure group showed a decreasing trend of insomnia, dreaminess, sweating and fatigue with the increase of working age (χ(2trend)=6.16, 7.99, P<0.05). The risk classification of binaural high-frequency hearing loss for workers in all noise positions until the age of 50 and 60 was negligible, the risk of occupational noise deafness was low for workers in stamping and welding noise positions until the age of 60. Conclusion: The occupational noise exposed to automobile manufacturing workers may cause certain harm to their nervous and auditory systems. Noise protection measures should be taken to reduce the risk of hearing loss and occupational noise deafness.

In vitro assessment of the DNA damage and senility of CD117+ stem cells collected from diabetic mice.

OBJECTIVE: Angiogenesis impairment is a common feature of diabetes mellitus (DM), whereas CD117+ bone marrow cells (BMCs) injury might be responsible for such complication. In this study, we studied the effect of hyperglycemia on the DNA damage and senility of CD117+ bone marrow cells. MATERIALS AND METHODS: We isolated CD117+ BMCs from the Streptozotocin (STZ) induced diabetes and healthy control mice. Oxidative stress was detected by flow cytometric analysis. γ-H2AX, which is the DNA damage mark, was detected by using Western blotting and immunofluorescence histochemistry. We also detected the expression of γ-H2AX and p16 by using Western blotting. RESULTS: Compared with the control mice, the level of reactive oxygen species (ROS) was increased significantly in the CD117+ BMCs collected from the diabetic mice (p<0.05), and the percentage of γ-H2AX positive cells was higher significantly (p<0.01). The expression of γ-H2AX and p16 was increased significantly in the CD117+ BMCs from the diabetic mice. CONCLUSIONS: Our experiments demonstrated the oxidative stress in CD117+ BMCs under DM conditions, while accelerating the DNA damage and senility in CD117+ BMCs as well.

Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of donor site.

From August of 1995 through July of 1998, 38 free anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. The overall success rate was 97 percent. Among 38 anterolateral thigh flaps, four were elevated as cutaneous flaps based on the septocutaneous perforators. The other 34 were harvested as myocutaneous flaps including a cuff of vastus lateralis muscle (15 to 40 cm3), either because of bulk requirements (33 cases) or because of the absence of a septocutaneous perforator (one case). However, vastus lateralis muscle is the largest compartment of the quadriceps, which is the prime extensor of the knee. Losing a portion of the vastus lateralis muscle may affect knee stability. Objective functional assessments of the donor sites were performed at least 6 months postoperatively in 20 patients who had a cuff of vastus lateralis muscle incorporated as part of the myocutaneous flap; assessments were made using a kinetic communicator machine. The isometric power test of the ratios of quadriceps muscle at 30 and 60 degrees of flexion between donor and normal thighs revealed no significant difference (p > 0.05). The isokinetic peak torque ratio of the quadriceps and hamstring muscles, including concentric and eccentric contraction tests, showed no significant difference (p > 0.05), except the concentric contraction test of the quadriceps muscle, which revealed mild weakness of the donor thigh (p < 0.05). In summary, the functional impairment of the donor thighs was minimal after free anterolateral thigh myocutaneous flap transfer.

The reliability of the 'Ortho Grid' in cephalometric assessment.

The reliability of cephalometric analysis using the Ortho Grid was assessed and compared with that of traditional tracing, digitization of radiographs and digitization of tracings. A total of fifty lateral skull radiographs were read using each of these methods on two different occasions. Use of the Ortho Grid was found to be the most reliable method in five of the seven measurements investigated.