Size-dependent biological effects on vascular endothelial cells induced by different particulate matters / 华中科技大学学报（医学）（英德文版）

The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different sizes on cardiovascular cells have not been well recognized. In this study, sub-cultured human umbilical vein endothelial cells (HUVECs) were exposed to increasing concentrations of pure quartz particles (DQ) of three sizes (DQPM1, <1 μm; DQPM3-5, 3-5 μm; DQPM5, 5 μm) and carbon black particles of two sizes (CB0.1, <0.1 μm; CB1, <1 μm) for 24 h. Cytotoxicity was estimated by measuring the activity of lactate dehydrogenase (LDH) and cell viability. Nitric oxide (NO) generation and cytokines (TNF-α and IL-1β) releases were analyzed by using NO assay and enzyme-linked immunoabsorbent assay (ELISA), respectively. It was found that both particles induced adverse biological effects on HUVECs in a dose-dependent manner. The size of particle directly influenced the biological activity. For quartz, the smaller particles induced stronger cytotoxicity and higher levels of cytokine responses than those particles of big size. For carbon black particles, CB0.1 was more capable of inducing adverse responses on HUVECs than CB1 only at lower particle concentrations, in contrast to those at higher concentrations. Meanwhile, our data also revealed that quartz particles performed stronger cell damage and produced higher levels of TNF-α than carbon black particles, even if particles size was similar. In conclusion, particle size as well as particle composition should be both considered in assessing vascular endothelial cells injury and inflammation responses induced by particles.

Size-dependent biological effects on vascular endothelial cells induced by different particulate matters / 华中科技大学学报（医学）（英德文版）

The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different sizes on cardiovascular cells have not been well recognized. In this study, sub-cultured human umbilical vein endothelial cells (HUVECs) were exposed to increasing concentrations of pure quartz particles (DQ) of three sizes (DQPM1, <1 μm; DQPM3-5, 3-5 μm; DQPM5, 5 μm) and carbon black particles of two sizes (CB0.1, <0.1 μm; CB1, <1 μm) for 24 h. Cytotoxicity was estimated by measuring the activity of lactate dehydrogenase (LDH) and cell viability. Nitric oxide (NO) generation and cytokines (TNF-α and IL-1β) releases were analyzed by using NO assay and enzyme-linked immunoabsorbent assay (ELISA), respectively. It was found that both particles induced adverse biological effects on HUVECs in a dose-dependent manner. The size of particle directly influenced the biological activity. For quartz, the smaller particles induced stronger cytotoxicity and higher levels of cytokine responses than those particles of big size. For carbon black particles, CB0.1 was more capable of inducing adverse responses on HUVECs than CB1 only at lower particle concentrations, in contrast to those at higher concentrations. Meanwhile, our data also revealed that quartz particles performed stronger cell damage and produced higher levels of TNF-α than carbon black particles, even if particles size was similar. In conclusion, particle size as well as particle composition should be both considered in assessing vascular endothelial cells injury and inflammation responses induced by particles.

Fit test and improvement of self-inhalation air-purifying dust respirator / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the fit of self-inhalation air-purifying dust respirator for Chinese workers, to improve the respirators according to Chinese facial features and to evaluate the protective effects of improved respirators.</p><p><b>METHODS</b>Two types of self-inhalation air-purifying dust respirators (cup respirators A1 and folding respirators B1) were tested by Condensation Nuclei Counting method (CNC) in 25 representative subjects (15 males and 10 females). According to the Chinese facial features and fit factors, A1 and B1 respirators were improved. The fit tests were performed for the improved A1 and B1 respirators.</p><p><b>RESULTS</b>The fit factors ≥ 100 served as the qualified standard of self-inhalation air-purifying dust respirators. The qualified rate for cup respirator A1 was 0.0%. Its geometric mean fit factor was 20.7 (6.9 ∼ 46.9). The qualified rate for cup respirator B1 was 4.0%. Its geometric mean fit factor was 26.0 (6.8 ∼ 154.9). After improvement, the qualified rates and fit factors significantly increased. The qualified rate for cup respirator A2 was 72.0% and geometric mean fit factor was 223.5 (2.2 ∼ 5932.7). There were significantly differences between respirator A1 and A2 (χ(2) = 25.09, P < 0.05). The qualified rate for cup respirator B2 was 88.0 % and geometric mean fit factor was 429.8 (41.5 ∼ 3692.9). The significant differences (χ(2) = 32.21, P < 0.05) between B1 and B2 were found.</p><p><b>CONCLUSION</b>To ensure the protective effects, the self-inhalation air-purifying dust respirators were designed according to Chinese facial features. The respirator fit test must be conducted when workers choose respirators.</p>

The relationship between fit characteristics of two kinds of self-inhalation air-purifying dust respirators and head-face dimensions of subjects / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the fitness characteristics of self-inhalation air-purifying dust respirators for representative subjects and to explore the influencing factors on fitness characteristics of respirators.</p><p><b>METHODS</b>According to the Chinese new bivariate fit test panel, 50 representative subjects were studied for using 2 kinds of self-inhalation air-purifying dust respirators. The N95 Companion from TSI was used to test the Fit factor (FF), and five representative facial dimensions (face width, bigonial breadth, nasal root breadth, face length and nose protrusion) were measured. Then chi-square test was used to compare the qualified rates of 2 kinds of respirators. The t-test was utilized to analyze the differences of facial dimensions between qualified samples and unqualified samples. Multiple linear regression models were also established to analyze the effects of facial dimensions on FF.</p><p><b>RESULTS</b>The qualified rate (86%) of folding respirators was significantly higher than that (68%) of cup respirators (P < 0.05). There were no significant differences of facial dimensions between qualified subjects and unqualified subjects for folding respirators. However, the face width, bigonial breadth and face length of qualified subjects were significantly larger than those of unqualified subjects for cup respirators (P < 0.01). The regression coefficient (0.31846) demonstrated that the positive effects of face length on mean log-transformed fit factor (MLFF) for all subjects with cup respirators (P < 0.05).</p><p><b>CONCLUSION</b>There were significant effects of respirator styles and head-face dimensions on the respirator fitness. There was a significant correlation between the respirator fitness and the facial dimensions for cup respirators.</p>

Study on the injury of vascular endothelial cells affected by dust particles from workplaces in pottery factories and tungsten mines / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>to assess direct adverse effects of occupational dusts from pottery factories and tungsten mines on vascular endothelial cells in vitro test.</p><p><b>METHODS</b>human umbilical vein endothelial cell (HUVEC) line HUV-EC-C were used as target cells. HUVEC were then treated with respirable dust particles from workplaces in pottery factories and tungsten mines in concentrations of 25, 50, 100, 200 and 400 microg/ml for 24 h. Standard quartz was used as control. LDH activity, cell viability, the release of NO and TNF-α levels were determined to assess the biological responses of the dust particles.</p><p><b>RESULTS</b>dose-response relationships between the dust concentrations and the enhancement of the LDH activity, the release of NO and TNF-α were found in both dust particles from pottery factories and tungsten mines. The cell viability decreased with the increase of dust concentration from 25 to 400 microg/ml. Compared with the dust particles from workplaces, the quartz dust induced significantly higher LDH activity (P < 0.05) after cultured with HUVEC. No significant difference of releases of NO were observed among the dust particles from workplaces and standard quartz. However, significantly higher levels of TNF-α were induced by standard quartz compared with dust samples from workplaces at concentrations of 200, 400 microg/ml.</p><p><b>CONCLUSION</b>occupational dust particles from workplaces and quartz could induce the injury and the releases of TNF-α from HUVEC.</p>

Two new anthropometric panels of respirator fit test for Chinese adult workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To develop two new respirator fit test panels using data from anthropometric survey of Chinese adult workers: bivariate panel and principal component analysis (PCA) panel for meeting the requirements of respirator fit design and testing and evaluate the applicability of the two different fit test panels for current Chinese workers.</p><p><b>METHODS</b>An anthropometric database based upon anthropometric data of current Chinese workers was used for panel design. The bivariate panel was based upon the bivariate distribution of the face length and face width measurements, and the PCA panel was developed using principal components analysis of 10 stable facial dimensions (minimum frontal breadth, face width, bigonial breadth, face length, interpupillary distance, head breadth, nose protrusion, nose breadth, nasal root breadth, subnasale-sellion length). The distribution of Chinese workers across the panels was used to analyze the panels' applicability for Chinese workers.</p><p><b>RESULTS</b>The bivariate panel and PCA panel developed in this study consisted of 10 cells and 8 cells respectively, covered 96.9% (male 95.4%, female 98.4%) and 96.5% (male 95.1%, female 98.1%) of the current Chinese workers, respectively. The distribution of workers across both panels was uniform. Each cell contained 4.6% - 21.7% of the population in the bivariate panel and 10.4% - 14.6% of the population in the PCA panel. The LANL full-face piece respirator fit test panel covered only 70.9% of the Chinese workers, It was thought to be no longer adequate for the Chinese adult workers.</p><p><b>CONCLUSION</b>New respirator fit test panels based on updated anthropometric database and distributions specific to Chinese workers may be more beneficial for applications in China.</p>