Silica exposure results in acute inflammatory response followed by chronic fibrotic change. The mechanism for the maintenance of silica-induced inflammation has not been understood yet. Apoptosis is a morphologically distinct form of programed cell death that plays major role during homeostasis and in many diseases including cancer, acquired immune deficiency syndrome and neurodegenerative disorders. Apoptosis is characterized by cell shrinkage, membrane blebbing and nuclear condensation. To demonstrate the involvement of apoptosis in underlying mechanism for the development of silica-induced pathological changes, this study was designed in vitro and in vivo models. In in vitro study, alveolar epithelial cell line (A549) was stimulated with silica and performed flow cytometry and DNA electrophoresis. In in vivo study, bronchoalveolar lavage (BAL) was done to count the total and apoptotic cells from silica-instilled rats. The results were as follows: 1. Apoptotic cell fraction of silica-treated groups (10 and 50 microgram/cm2) was significantly higher than that of control group. 2. Genomic DNA from silica-treated groups (10 and 50 microgram/cm2 ) showed DNA ladder in agarose gel electrophoresis, while group of 1 microgram/cm2 didn't. 3. Total cell number and apoptotic cell number of BAL fluid from silica-instilled rats (10, 20 and 40 mg/kg) were significantly higher than those of control. 4. Silica induced apoptosis of cells in BAL fluid was confirmed by microscopic observation with nuclear fragmentation. These results suggest that apoptosis may contribute to development of silica-induced pathological changes.
Acquired Immunodeficiency Syndrome ; Animals ; Apoptosis* ; Blister ; Bronchoalveolar Lavage ; Cell Count ; Cell Death ; DNA ; Electrophoresis ; Electrophoresis, Agar Gel ; Epithelial Cells ; Flow Cytometry ; Homeostasis ; Inflammation ; Membranes ; Microscopy ; Neurodegenerative Diseases ; Rats ; Silicon Dioxide* ; Silicosis

Executing detailed examination for cumulative trauma disorders(CTD) for all the workers with repetitive operators is not desirable considering the cost-effectiveness. Screening test with subjective symptoms, physical examination and hand strength test to detect the proper subject for secondary detailed examination is needed. The purpose of this study was to determine normal values for grip and pinch(tip, lateral and palmar) strength to be used as a screening tool for CTD. Total of 1,018 healthy subjects without related past occupational or medical history were examined with Jamar dynamometer and pinch gage. Each hand was checked twice in a posture recommended by American Society of Hand Therapists, and higher value was accepted. The results were as follows, 1. The mean grip strength of right hand in right-handed man was 47.7 kg, and 27.2 kg in woman. The mean tip pinch strength of right hand in right-handed man was 6.2 kg, and 3.9 kg in woman. The mean lateral pinch strength was 9.0 kg in man, and 5.5 kg in woman. And the mean palmar pinch strength was 9.3 kg in man, and 6.9 kg in woman. There was no significant differences in dominant hand power according to the right or the left hand dominances. 2. Selecting 10 percentile value for screening criteria for CTD, 10 percentile value of trip strength was 38 kg in man and 20 kg in woman. And that of tip pinch strength was 4 kg in man and 2 kg in woman, lateral pinch strength was 6 kg and 4 kg each, palmar pinch strength was 6 kg and 5 kg each. 3. Grip and all three pinch strengths of man showed positive correlation with age, height and weight, but in the cases of woman, only grip strength showed positive correlation with height and weight. 4. In cases of right-handed persons, dominant hand showed higher grip strength compared to the contralateral hand in 70.9% of males, and 72.9% of females. And the mean differences of bilateral grip strength was 2.7 kg(5.2%) in male, and 1.7 kg(5.7%) in female. But in the cases of left-handed persons, dominant hand did not show the significant difference in strength compared to the contralateral hand.
Cumulative Trauma Disorders* ; Female ; Hand ; Hand Strength* ; Humans ; Male ; Mass Screening* ; Physical Examination ; Pinch Strength* ; Posture ; Reference Values