[Sensitivity and specificity of nucleic acid testing in close contacts of COVID-19 cases in Guangzhou].

Objective: To analyze the sensitivity and specificity of SARS-CoV-2 nucleic acid testing in 20 348 close contacts of COVID-19 cases in different prevention and control stages in Guangzhou and to provide scientific evidence for optimizing epidemic response strategies. Methods: A total of 20 348 close contacts of COVID-19 cases in Guangzhou were traced between February 21 and September 22,2020. All the close contacts were tested for the nucleic acid of SARS-CoV-2. The sensitivity and specificity of nucleic acid testing and diagnosis in the different prevention and control stages were compared. Results: In 20 348 close contacts, 12 462 were males (61.24%), the median (P25,P75) of age of them was 31.0 years (23.0,43.0), the median number (P25,P75) of nucleic acid testing for them was 2.0 (1.0,3.0), and the median (P25,P75) of their quarantine days was 12.0 (8.0,13.0) days, respectively. A total of 256 COVID-19 cases were confirmed in the close contacts after seven nucleic acid tests. In the 1st, 2nd, 3rd and 7th nucleic acid testing, the sensitivity and specificity were 69.14% and 99.99% (177 cases confirmed), 89.84% and 99.99% (230 cases confirmed), 97.27% and 99.99% (249 cases confirmed), and 100.00% and 99.98%, respectively. In the three stages of COVID-19 prevention and control in China: domestic case stage, imported case stage, and imported case associated local epidemic stage, the sensitivity of the 1st nucleic acid testing was 70.68%, 68.00% and 67.35%, and the specificity was 99.98%, 100.00% and 100.00%, respectively. Conclusions: The sensitivity of nucleic acid testing in the close contacts at the different stages were consistent with slight decrease, which might be related to the increased proportion of asymptomatic infections in the late stage of epidemic prevention and control with COVID-19 in Guangzhou. It is suggested to give three nucleic acid tests to improve the sensitivity and reduce false negative risk.

[Analysis of influencing factors of high-frequency hearing loss among male noise workers in an automobile manufacturing enterprise].

Objective: To analysis of high-frequency hearing loss status and risk factors among male noise workers in an automobile manufacturing enterprise in Guangzhou. Methods: From February 2020, a cluster sampling method was used to select 3486 male workers exposed to noise in an automobile manufacturing enterprise in Guangzhou in 2018. After screening, 2608 were selected as the research objects. Pure tone hearing threshold test, noise exposure level test and questionnaire survey were conducted, and the cumulative noise exposure was calculated. Chi square test and unconditional logistic regression were used to analyze the correlation between various factors and high frequency hearing loss. Results: The detection rate of high-frequency hearing loss in noise exposed workers was 34.20% (892/2608) , there were significant differences in the two groups among age, marital status, years of noise exposure, noise exposure equivalent A sound level, CNE, different working hours and exposure to electromagnetic radiation (P<0.05) . Multiple logistic regression analysis showed that age, CNE and exposure to electromagnetic radiation were independent risk factors for high-frequency hearing loss (P<0.05) , three shifts and two shifts were the protective factors for the occurrence of high-frequency hearing loss (OR=0.523, P<0.01) . Conclusion: Noise exposure is the main influencing factor of high-frequency hearing loss of noise-receiving workers in automobile manufacturing enterprises. Enterprises should strengthen noise control in the workplace, improve the working environment of electromagnetic radiation, and implement a scientific and healthy work shift system.

[Epidemiological characteristics of imported COVID-19 cases in Guangzhou].

Objective: To understand the epidemiological characteristics of imported COVID-19 cases in Guangzhou and provide scientific basis for the prevention and control of the disease. Methods: The data of imported COVID-19 in Guangzhou reported as of April 1, 2020 were collected from National Notifiable Disease Report System of China. The software Excel 2010 and SPSS 19.0 were applied for data cleaning and statistical analysis. Results: As of April 1, 2020, a total of 103 imported COVID-19 cases had been reported in Guangzhou, in which 92 were confirmed cases and 11 were asymptomatic infection cases. The number of the confirmed imported cases accounted for 11.4% (92/806) in of the total in China at the same time. The male to female ratio of the cases was 1.58∶1 (63∶40). The median age of the cases was 31 years (P(25)-P(75):22-40 years), range of age was 11-63 years. The main occupational distributions of the cases were business services (41/103, 39.8%) and students (36/103, 35.0%). The imported cases whose destinations were 19 provinces and municipalities rather than Guangdong after entering the country accounted for 43.7%. The main source countries of infections were the United Kingdom (27/103, 26.2%), the Philippines (13/103, 12.6%), the United States (13/103, 12.6%) and Nigeria (7/103, 6.8%). There were 34 inbound flights from which the imported COVID-19 cases were detected, in which 10 flights (10/34, 29.4%) were found to carry more than 3 cases, with an average voyage time of (11.14±0.53) hours. A total of 29 imported cases(28.2%) showed symptoms before entering the country, and 65 cases (63.1%) had been isolated before the onset of the disease. The mean free activity time of the isolated cases after the onset was (6.76±0.79) days. The average number of the imported cases' close contacts was 53. There were 13 clusters of COVID-19 caused by the imported cases, involving 36 cases (including 1 imported associated case). Conclusions: The sources of the imported COVID-19 cases in Guangzhou were widely distributed, and no cases had been found to be infected on the flights. In the early stage of the imported epidemic, there was high risk for the spread of the epidemic. Strengthened prevention and control of imported COVID-19 effectively reduced the of transmission risk of COVID-19 in communities.

[Analysis of common gynecological diseases in 1142 married female workers].

Objective: To understand the prevalence of gynecologic diseases among married female workers. Methods: The data of married female workers who underwent occupational health examination in a physical examination center from January to December 2017 were collected. The relationship between the detection of common gynecological diseases, age and occupational types examined by gynecological routine, TCT, breast B-mode ultrasound, uterus and appendix B-mode ultrasound were analyzed. Results: Among the 1142 female workers, the total detection rate of reproductive tract infections was 67.25% (768/1142), the total detection rate of breast-related diseases was 75.22% (859/1142) ; the total detection rate of gynecological tumors and benign lesions was 14.71% (168/1142). The detection rate of breast hyperplasia was the highest 67.08% (766/1142), followed by vaginitis 51.66% (590/1142). Among the abnormalities detected in breast-related diseases, gynecological tumors and benign lesions, the highest detection rate was found in public institutions (85.66% and 27.13%), and the lowest was found in factory workers (70.24% and 7.89%). With the increase of age, the detection rate of breastrelated diseases (breast hyperplasia, breast cyst), gynecological tumors, benign lesions (uterine myoma), and Nessler's cyst abnormalities in married female workers increased (χ(2)(trend)=7.647、21.653、107.411、53.802, P<0.05), while the detection rate of columnar epithelium of cervix decreased (χ(2)(trend)=7.404, P<0.05). There was no significant difference in the total detection rate of reproductive tract infectious diseases (vaginitis, cervical polyps, cervical hypertrophy) among married famale workers of different ages (P<0.05) . Conclusion: The common gynecological diseases of married female workers are affected by many factors such as age and occupation. Health examination and health education should be carried out regularly to reduce the incidence of gynecological diseases among female workers according to different ages and occupations.

[An analysis of work-related musculoskeletal disorders and ergonomic loads in male welders in shipbuilding industry].

Objective: To investigate the prevalence of work-related musculoskeletal disorders (WMSDs) in male welders in different work areas of shipbuilding industry based on their operational working position and body position characteristics and to analyze the operational positions and ergonomic loads. Methods: In February 2017, 412 male welders from the hull and block work areas of a large ship factory were selected by stratified sampling. The prevalence and effects of WMSDs within a year were investigated using the Nordic Musculoskeletal Disorders Questionnaire, and a rapid exposure checklist was used to obtain the ergonomic load index by comprehensive scoring; the exposure-response relationship between the ergonomic loads and WMSDs symptoms of subjects in the hull and block work areas was evaluated. Results: Among the male welders working in the hull work area of shipbuilding industry, WMSDs occurred more commonly in the neck, lower back/waist, and legs, accounting for 53.16% (126/237) , 51.90% (123/237) , and 41.77% (99/237) , respectively; among those working in the block work area, WMSDs occurred more commonly in the lower back/waist, wrist, and legs, accounting for 52.57% (92/175) , 49.14% (86/175) , and 45.14% (79/175) , respectively. There were significant differences in the distribution of cases of pain within the last 7 days and one month, pain lasting more than one month, or absence from work due to pain within a year in the four positions between the two work areas (P<0.05). In the hull work area, high and extremely high exposure levels were mainly seen in the neck, lower back/waist, and legs, accounting for 76.79%(182/237), 69.20%(164/237), and 59.49%(141/237), respectively; in the block work area, high and extremely high exposure levels were mainly seen in the lower back/waist, wrist, and legs, accounting for 77.71%(136/175), 50.29% (88/175), and 46.29% (81/175), respectively. The detection rates of WMSDs in these four positions significantly increased as the exposure levels rose (P<0.01). Conclusion: The WMSDs of male welders working in the hull and block work areas of shipbuilding industry occurs more commonly in the lower back/waist and legs. The risk of WMSDs symptoms increases with the rise of ergonomic load.

[Effect of long-term low-concentration mixed benzene exposure on male peripheral blood in an automobile manufacturing enterprise].

Objective: To investigated the effect of long-term low-concentration mixed benzene exposure on peripheral blood of male workers. Methods: A case-control study was conducted to select 452 male workers exposed to mixed benzene (benzene, toluene, xylene) for five consecutive years from January 2012 to December 2016 in an automobile manufacturer as case group, and 438 male administrative and logistic managers who underwent physical examination during the same period as control group. The peripheral blood of the two groups was tested and compared, and the occupational hazards in the workplace were detected. Results: There were low dose exposure to mixed benzene in the enterprise, but the test results met the occupational exposure limit requirements. During the five years from 2010 to 2016, between the two groups of workers, the mean values of WBC, NEUT, RBC and Hb were statistically different (P<0.05). There was no statistical difference (P>0.05) in the mean value of PLT. The abnormal rate of main peripheral blood indexes in the control group was higher than that in the exposed group. There were significant differences in NEUT, RBC and Hb (P< 0.05), but no significant differences in WBC and PLT (P>0.05). Conclusion: It can not be concluded that long-term low-concentration mixed benzene exposure can cause the change of peripheral blood index.

[Current prevalence and prevention of work-related musculoskeletal disorders among physicians for internal medical examination in tertiary hospitals in a city of China].

Objective: To investigate the current prevalence and prevention of work-related musculoskeletal disorders (WMSDs) among physicians for internal medical examination, and to provide a theoretical basis for the prevention and treatment of WMSDs in physicians for internal medical examination. Methods: In February 2017, 326 physicians for internal medical examination were randomly selected from 5 general tertiary hospitals and 2 specialized tertiary hospitals in a city of China. A questionnaire was designed according to the Nordic Musculoskeletal Questionnaire and the occupational features of doctors in China to investigate the prevalence of musculoskeletal pain over the past year, the cognitive attitude to WMSDs, the knowledge of WMSDs prevention, and ways to get the knowledge of WMSDs prevention. Results: In the tertiary hospitals of this city, the symptoms of WMSDs were mainly seen in the wrist (75.78%) , neck (67.19%) , and lower back (58.59%) among male physicians, and in the wrist (73.74%) , lower back (70.95%) , and upper back (60.89%) among female physicians. Compared with the female physicians, the male physicians had a significantly increased detection rate of symptoms of WMSDs in the neck (P<0.05) and significantly reduced detection rates of symptoms of WMSDs in the upper and lower back (P<0.05). There were significant differences between the detection rates of symptoms of WMSDs in the neck, wrist, and lower back within the past 12 months, 7 days, and >1 month (P<0.01). The rates of knowledge of the severity and prevention of WMSDs were significantly different between the physicians with different working years and professional titles (P<0.01) . Conclusion: Among the physicians for internal medical examination in the tertiary hospitals of this city, WMSDs are mostly seen in the wrist, neck, and waist, and the knowledge of WMSDs prevention varies with different working years and professional titles.

Molecular cloning, functional verification, and evolution of TmPm3, the powdery mildew resistance gene of Triticum monococcum L.

Powdery mildew (Pm) is one of the most harmful diseases in wheat. Three Pm-resistance genes, Pm3, Pm21, and Pm8, have been cloned but most Pm3/Pm8 alleles have lost their resistance to Pm in hexaploid wheat. In this study, a new Pm3 homolog gene (TmPm3) was isolated from Triticum monococcum L. using a homology-based cloning strategy, being the first report of a functional Pm3 homolog gene from a diploid wheat species. The transient expression of TmPm3 in leaf epidermal cells showed that over-expressed TmPm3 could significantly inhibit the penetration of Blumeria graminis f. sp tritici conidia spores and the formation of haustoria. Sequence analysis of Pm3 alleles shed new light on the evolution of Pm3 genes, providing a better understanding of the molecular basis of disease resistance. This study also suggested that homology-based cloning of resistance genes is a feasible method for the isolation of functional resistance genes from wheat germplasm.

Effects of the proteasome inhibitor, bortezomib, on cytodifferentiation and mineralization of periodontal ligament cells.

BACKGROUND AND OBJECTIVE: The proteasome inhibitor, bortezomib, is known to induce osteoblastic differentiation in a number of cell lines, such as mesenchymal stem cells and osteoblastic precursor cells. As periodontal ligament (PDL) cells are multipotent, we examined whether bortezomib may induce the differentiation of PDL cells into hard-tissue-forming cells. MATERIAL AND METHODS: A mouse PDL clone cell line, MPDL22 cells, was cultured in mineralization medium in the presence or absence of bortezomib. Expression of calcification-related genes and calcified-nodule formation were evaluated by real-time PCR and Alizarin Red staining, respectively. RESULTS: Bortezomib increased the expression of calcification-related mRNAs, such as tissue nonspecific alkaline phosphatase isoenzyme (ALPase), bone sialoprotein (Bsp), runt-related transcription factor 2 (Runx2) and osteopontin, and calcified-nodule formation in MPDL22 cells. These effects were induced, in part, by increasing the cytosolic accumulation and nuclear translocation of ß-catenin, leading to an increase in expression of bone morphogenetic protein (Bmp)-2, -4 and -6 mRNAs. In addition, bortezomib enhanced BMP-2-induced expression of Bsp and osteopontin mRNAs and increased calcified-nodule formation in MPDL22 cells. CONCLUSION: Bortezomib induced cytodifferentiation and mineralization of PDL cells by enhancing the accumulation of ß-catenin within the cytosol and the nucleus and increasing the expression of Bmp-2, -4 and -6 mRNAs. Moreover, bortezomib enhanced the BMP-2-induced cytodifferentiation and mineralization of PDL cells, suggesting that bortezomib may be efficacious for use in periodontal regeneration therapy.

Involvement of miR-30c in resistance to doxorubicin by regulating YWHAZ in breast cancer cells.

MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.

Involvement of miR-30c in resistance to doxorubicin by regulating YWHAZ in breast cancer cells

MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.

Coronary heart disease and chronic periodontitis: is polymorphism of interleukin-6 gene the common risk factor in a Chinese population?

OBJECTIVES: Coronary heart disease (CHD) and chronic periodontitis (CP) both are multifactorial chronic diseases and related to inflammation. Interleukin-6 (IL-6) plays an important role in the pathogenesis of inflammatory diseases. The purpose of the study was to investigate the association among IL-6 gene polymorphisms, CP and CHD susceptibility in a Chinese population. MATERIAL AND METHODS: The investigation was conducted as a case-control study involving 505 individuals: 113 patients with CHD and CP, 84 patients with CHD, 178 patients with CP and 130 control individuals. The polymorphisms of IL-6 gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism. Relationships between the distributions of the genotypes and risk factors were also assessed. RESULTS: Mutations at the loci -174 G/C, -597 G/A of IL-6 were rare in a Chinese population. No significant difference for IL-6-572C/G polymorphism was detected among moderate CP group, severe CP group and control (P = 0.312 and 0.481), significant differences were found between CHD groups and non-CHD groups (P ≤ 0.001). After adjustment for CHD risk factors, the G allele resulted in an increased risk (OR = 1.676-1.856), the GG/CG genotype was nearly two times higher risk compared to CC genotype (OR = 2.010-2.136). CONCLUSIONS: IL-6-572C/G polymorphism did not correlate with CP susceptibility, but might be a potential risk factor for CHD in a Chinese population.

Association among interleukin-6 gene polymorphism, diabetes and periodontitis in a Chinese population.

OBJECTIVES: Diabetics significantly increase risk for periodontitis. Interleukin-6 (IL-6) gene polymorphism may play certain roles in the progression of periodontitis with diabetes. The purpose of this study was to assess the association among IL-6 gene polymorphisms, type 2 diabetes mellitus (T2DM) and chronic periodontitis (CP) in a Chinese population. MATERIAL AND METHODS: DNA was obtained from 159 patients with CP, 88 patients with T2DM, 110 patients with CP&T2DM and 135 control subjects. The -174/-572/-597 polymorphisms of IL-6 gene were investigated by restriction fragment length polymorphism of polymerase chain reaction products. The results were further confirmed by sequencing. Significance was set at P < 0.008 after Bonferroni correction. RESULTS: Among four groups, CP&T2DM group showed the lowest IL-6-572 CC genotype and C-allele frequencies (54.5% and 74.1%). In this regard, there were significant differences between CP&T2DM group and the control group [P = 0.006, odds ratio (OR) = 0.475, 95% CI: 0.279-0.808 and P = 0.002, OR = 0.502, 95% CI: 0.319-0.788 respectively]. Logistic regression with adjustment for age, gender, body mass index, smoking and stress showed no significant difference in terms of IL-6-572 genotypes (P = 0.058, OR= 0.523, 95% CI: 0.268-1.022). CONCLUSIONS: The IL-6-572 genotype and allele distributions are unique to subjects with CP&T2DM in a Chinese population.

[Molecular tagging of a major powdery mildew resistance gene MlG in wheat derived from wild Emmer by using microsatellite marker].

Powdery mildew caused by Erysiphe graminis f. sp. tritici is one of the most important wheat diseases in many regions of the world. Breeding for resistant cultivars has been proved to be an effective and environmentally safe method to control diseases in wheat production. It is necessary to search for more resistance genes for the diversification of resistance genes in wheat breeding. An Isreali wild emmer wheat (Triticum dicoccoides) accession "G-305-M" was found resistant to the prevailing E. graminis f. sp. tritici isolate Race No. 15 in Beijing region. The powdery mildew resistance has been transferred from G-305-M into common wheat by crossing and backcrossing (G-305-M/781//Jing 411* 3). Genetic analysis showed that the resistance was controlled by a single dominant gene at the seedling stage. A segregating BC2F3 family of the cross "G-305-M/781//Jing 411* 3" with 167 plants was chosen for SSR analysis. Totally 96 wheat microsatellite primer pairs were screened, only one primer pair WMS570 could generate polymorphic DNA fragments between the resistant and susceptible plants. After evaluating this polymorphic marker in the segregating population, the microsatellite locus Xgwm570 mapped on chromosome 6AL was found to be linked to the resistance gene, with the estimated genetic distance of 14.9 +/- 3.0 cM. Based on the origin and chromosomal location of the gene, it is suggested that the resistance gene derived from G-305-M should be a novel Pm gene and is temporarily designated MlG.