OBJECTIVETo investigate the effects of composite grinding dusts on rat respiratory system.

METHODSRats were administrated with grinding dusts by intratracheal injection. After 2 weeks, the total numbers of cells, the percentage of differential cell, the survival rate of cell, and the activity of lactate dehydrogenase(LDH) and alkaline phosphatase(ALP) in bronchoalveolar lavage fluid were analyzed.

RESULTSAlong with increasing concentration of grinding dusts, the total number of cells in lavage also increased, and was more than that in quartz group. Compared with control group, the percentage of neutrophil in lavage of rats treated with grinding dust and quartz significantly increased and meanwhile that of macrophage significantly decreased[PMN: quartz group (33.83 +/- 4.54)%; grinding dusts group (26.50 +/- 3.99)%, (36.00 +/- 3.58)%, (38.00 +/- 2.10)% at 10, 25, 50 mg/ml respectively. Macrophages: quartz group (62.17 +/- 4.54)%; grinding dusts group (70.83 +/- 3.66)%, (60.83 +/- 2.14)%, (58.17 +/- 2.48)%] while those in control group were (2.83 +/- 0.75)%, (95.67 +/- 1.21)% respectively. The cell survival rate in lavage in control group was 80%, but that in grinding dust and TiO2 group significantly decreased(P < 0.01). The activity of LDH and ALP in all rats treated with dusts obviously increased, and there was significant difference compared with control group(P < 0.01 or P < 0.05). Furthermore, there was significant difference between grinding dust group and quartz group, and between grinding dust group and TiO2 group respectively.

CONCLUSIONMetal grinding dust is very harmful to rat's lung cells and may cause fibrogenesis in the lungs.

Alkaline Phosphatase ; metabolism ; Animals ; Bronchoalveolar Lavage Fluid ; chemistry ; cytology ; Dust ; L-Lactate Dehydrogenase ; metabolism ; Lung ; pathology ; Metals ; Rats

OBJECTIVETo establish suitable predictive equations of lung function for occupational population in North China.

METHODSA total of 5 002 on the job or retired healthy adults from five enterprises in North China with category of mild or moderate work intensity underwent spirometry using a Chest HI-198 spirometer and the procedures recommended by the American Thoracic Society, were a sample.

RESULTSThe data of 3 913 subjects were used. A normal distribution of our data was shown using the normality test and distribution curve. Univariate analysis showed that both age and height were significantly correlated with FVC, FEV(1), FEV(1)/FVC (%) and MMF. Further multiple linear stepwise regression analysis indicated that the levels of FVC, FEV(1), FEV(1)/FVC (%) and MMF were highly influenced by age, height, and weight rather than chest circumference. Thus, only age, height, and weight were introduced into our regression equations. Data from the studied subjects and other source were utilised to examine the validity of the equations and a high accordance rate (> 90%) was obtained. No significant difference (P > 0.05) was found in the predictive values between the simplified equations and equations in which more variables were included.

CONCLUSIONThe studied predictive equations for male non-smokers, female non-smokers, and male smokers were established based on data from a large occupational population. These equations should be more applicable for evaluating lung ventilatory function of occupational populations in North China.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; China ; Female ; Humans ; Male ; Middle Aged ; Occupational Exposure ; Occupations ; Predictive Value of Tests ; Pulmonary Ventilation ; Reference Values ; Regression Analysis ; Reproducibility of Results ; Respiratory Function Tests ; standards ; Vital Capacity ; Young Adult