G Trujillano | Search PubMed

PubMed1995

Subclinical signs of kidney dysfunction following short exposure to silica in the absence of silicosis.

Signs of kidney dysfunction detectable in urinary protein excretion were searched for in a group of 86 silica-exposed workers who were compared to 86 control subjects matched for age, smoking status and body mass index. No worker had any clinical, spirometric or radiographic sign of silicosis, and exposure duration averaged 15.2 months (range: 11-20). An increase in the urinary excretion of albumin, transferrin, retinol-binding protein and N-acetyl-beta-D-glucosaminidase was found in the exposed group, and the prevalences of pathological values were also elevated in this group. By contrast, both groups had similar serum levels of creatinine and beta 2-microglobulin. These results strongly suggest that occupational exposure to silica may lead to subclinical renal effects after less than 2 years and in the absence of silicosis.

Adult↗

PubMed1994

Early decrease of serum Clara cell protein in silica-exposed workers.

Clara cell protein (CC16) is a 16 kDa protein secreted by nonciliated cells of the tracheobronchial tree; it has recently been proposed as a peripheral marker of respiratory epithelial injury. The concentration of CC16 was measured in the serum and, when available, in the sputum of 86 miners exposed to silica and of 86 control subjects matched for age, body mass index and smoking status (26 lifelong nonsmokers and 60 current smokers in both groups). Workers were exposed to silica-rich dust in a quarry for 15.2 months on average. No difference between exposed and control workers could be detected with regard to respiratory symptoms, chest radiographs or lung function tests. By contrast, the concentration of CC16 in serum was decreased in silica-exposed workers (geometric mean 12.3 micrograms.l-1) compared to controls (16.3 micrograms.l-1). The decrease was found both in lifelong nonsmokers (14.7 vs 21.9) and current smokers (11.3 vs 14.5). In the latter, tobacco smoking caused a decrease of serum CC16 that was additional to that associated with silica exposure. The determination of CC16 in sputum samples, judged to be reliable on the basis of the CC16/alpha-amylase concentration ratio (mostly from smokers), also revealed a reduction of CC16 following silica exposure (46.2 vs 106 mg.l-1). We conclude that alterations in the serum concentrations of CC16 probably reflect very early toxic effects of silica particles on the respiratory epithelium. This reinforces the view that serum CC16 is a sensitive marker, which might improve our ability to detect exposure to chemicals potentially harmful to the respiratory tract.

Adult↗