Biomedical subjects

K S Fong

Publications and source records attributed to K S Fong.

20 records · Page 2Linked to original sources

PubMed1993

An evaluation of the significance of mouth and hand contamination for lead absorption in lead-acid battery workers.

The present study was conducted to evaluate the role of ingestion through hand and mouth contamination in the absorption of lead in 25 lead-acid battery workers. Levels of personal exposure to airborne lead ranged from 0.004 to 2.58 mg/m3 [geometric mean 0.098, with 25% of samples exceeding threshold limit values (ACGIH) of 0.15 mg/m3]; the mean (SD) blood lead level was 48.9 (10.8) micrograms/dl. Mean hand lead contents increased 33-fold from preshift levels on Monday mornings (33.5 micrograms/500 ml) to midshift levels on Thursday afternoons (1121 micrograms/500 ml). Mouth lead contents increased 16-fold from 0.021 micrograms/50 ml on Mondays to 0.345 micrograms/50 ml on Thursdays. The typical Malay racial habit of feeding with bare hands and fingers without utensils (closely associated with mouth and hand lead levels on Mondays) explained the bulk of the variance in blood lead levels (40%), with mouth lead on Thursdays (closely associated with poor personal hygiene) explaining a further 10%. Air lead was not a significant explanatory variable. The implementation of a programme of reinforcing hand-washing and mouth-rinsing practices resulted in a reduction of the blood lead level by 11.5% 6 months later. These results indicate that parenteral intake from hand and mouth contamination is an important cause of lead absorption in lead-exposed workers.

Adolescent↗

PubMedDate not supplied

Anti-Fas antibody differentially regulates apoptosis in Fas ligand resistant carcinoma lines via the caspase 3 family of cell death proteases but independently of bcl2 expression.

Deregulation of cell death pathways is an important feature of tumorigenesis. Fas, a member of the tumor necrosis factor receptor superfamily, is a transmembrane protein that can transduce cell death signals via a proteolytic cascade upon crosslinking or ligand binding. Fas has been implicated in the cell turnover of normal stratified squamous epithelia. To determine if altered Fas mediated cell death pathways participate in epithelial tumorigenesis, we examined squamous cell carcinoma (SCC) lines for sensitivity to Fas ligand (FasL) or an agonistic anti-Fas antibody. All cell lines examined were resistant to FasL mediated cell death. The carcinoma cell line SCC71 was also highly resistant to anti-Fas antibody. Another line, SCC9, underwent rapid cell death with characteristic features of apoptosis after exposure to anti-Fas antibody. However, binding of both FasL and anti-Fas antibody recruited downstream effector molecules to the Fas cytoplasmic domain in both SCC9 and SCC71 cells. Inhibition of the caspase 3- but not the ICE family of cell death proteases blocked apoptosis in SCC9 cells independently of expression of the anti-apoptotic protein bcl2. We concluded that Fas differentially mediates apoptosis in SCC lines by activation of caspase 3 family members but independent of bcl2 expression.

Animals↗