China ; Electric Power Supplies ; Occupational Health

Objective:To investigate the correlation between variations in mitochondrial DNA (mtDNA) control region (D-loop) and keloids.Methods:A total of 216 patients with keloids were collected from Department of Dermatology, the First Affiliated Hospital of Kunming Medical University from 2016 to 2019. Total DNA was extracted from peripheral blood samples of all the patients, as well as keloid tissues and perilesional normal skin tissues of 25 patients with keloids. Peripheral blood samples were collected from 299 health checkup examinees without keloids in Health Examination Center, the Affiliated Hospital of Yunnan University, who served as controls. PCR amplification and Sanger sequencing were performed on the mtDNA D-loop region, and mutation sites in each sample were analyzed by comparisons with the revised Cambridge Reference Sequence (rCRS) . Haplogroups were assigned in the 2 groups by using Phylotree-mtDNA tree Build 17. Mutations in the mtDNA D-loop region were compared among keloid tissues, perilesional normal skin tissues and peripheral blood samples. A median-joining network was constructed via network 5.0 software. Binary logistic regression analysis was performed to investigate the correlation between haplogroup frequencies and the occurrence of keloids, and chi-square, t and t′ tests were used to analyze clinical data. Results:Among the 216 patients with keloids, variations in mtDNA D-loop region were classified into 10 haplogroups, including A, B, D, R9, G, M*, M7, M8, M9 and N9, with the haplogroups R9 and M9 showing the highest (21.3%, 46/216) and lowest (0.9%, 2/216) frequencies respectively. The frequencies of haplogroups M7 ( P=0.040, OR=0.248, 95% CI: 0.066 - 0.937) and N9 ( P=0.048, OR=0.191, 95% CI: 0.037-0.986) were significantly lower in the patients with keloids than in the controls. The median-joining network plot showed that the distribution pattern of the haplogroup M7 differed between the patients with keloids and controls. Significantly less number of lesional sites and younger age of onset were observed in the patients with haplogroup M7 compared with those with non-M7 haplogroups ( P=0.000 1, 0.045, respectively) . Conclusion:The haplogroup M7 is correlated with the occurrence of keloids, and may be a potential protective factor for keloid formation.

To revise GBZ 188 Technical Specification for Occupational Health Surveillance based on national laws, regulations, standards, specifications and legal documents of occupational disease, and combination with the actual situation in China. The main modifications are as follows: the occupational health surveillance for workers exposed to toluene (xylene may implement by reference), bromopropane, methyl iodide, ethylene oxide, chloroacetic acid, indium and its compounds, coal tar, coal tarasphalt, asphalt, β-naphthylamine, dust of metal and its compounds(tin, iron, antimony, barium and its compounds), hard metal dust, erionite dust, low temperature, laser, tick-borne encephalitis virus, Borrelia burgdorferi, and human immunodeficiency virus, for scraper or grind operators, and underground workers using squatting or kneeling position, crawling position, side-lying position, or shoulder position for a long period of time are included. The emergency health screening for workers exposed to arsenic, fluorine and its inorganic compounds, and acrylamide are included. The occupational medical examination (OME) for workers exposed to amino and nitro compounds of benzene, phosgene, monomethylamine, organic fluorine and dimethyl sulfate has been adjusted and made mandatory, with corresponding assessments required upon leaving the job. The special occupational health surveillance for workers exposed to mycobacterium tuberculosis and hepatitis virus is removed. The OME conclusion of reexamination is removed, and standardize recheck/additional inspection requirements. The optional items in OME performed before, during and after leaving post are removed, but the optional items in emergency medical examination are retained. Additional OME items are added. The Guideline for OME Summary Reports is added as informative appendix, and so on. The revised GBZ 188 Technical Specification for Occupational Health Surveillance is more scientific and practical.