Gene expression and activity of antioxidant enzymes in the blood cells of workers who were occupationally exposed to lead

Novel biospectroscopy sensor technologies towards environmental health monitoring in urban environments

Biospectroscopy is an emerging inter-disciplinary field that exploits the application of sensor technologies [e.g., Fourier-transform infrared spectroscopy, Raman spectroscopy] to lend novel insights into biological questions. Methods involved are relatively non-destructive so samples can subsequently be analysed by more conventional approaches, facilitating deeper mechanistic insights. Fingerprint spectra are derived and these consist of wavenumber-absorbance intensities; within a typical biological experiment, a complex dataset is quickly generated. Biological samples range from biofluids to cytology to tissues derived from human or sentinel sources, and analyses can be carried out ex vivo or in situ in living tissue. A reference range of a designated normal state can be derived; anything outside this is potentially atypical and discriminating chemical entities identified. Computational approaches allow one to minimize within-category confounding factors. Because of ease of sample preparation, low-cost and high-throughput capability, biospectroscopy approaches herald a new greener means of environmental health monitoring in urban environments.

The metabolism of carbohydrates and lipid peroxidation in lead-exposed workers

The present study was undertaken to estimate the effect of occupational exposure to lead on the blood concentration of glucose and several enzymes involved in glycolysis, the citric acid cycle, and the pentose phosphate pathway. To estimate the degree of lipid peroxidation, the concentrations of conjugated dienes were determined.

The examined group included 145 healthy male employees of lead–zinc works. Taking into account the mean blood lead levels, the examined group was divided into two subgroups. The control group was composed of 36 healthy male administrative workers.

The markers of lead exposure were significantly elevated in both subgroups when compared with the controls. There were no significant changes in fasting glucose concentration and fructose-1,6-bisphosphate aldolase activity in the study population. The concentration of conjugated dienes was significantly higher in both subgroups, whereas the activity of malate dehydrogenase was significantly higher only in the group with higher exposure. The activities of lactate dehydrogenase and sorbitol dehydrogenase were significantly decreased in the examined subgroups. The activity of glucose-6-phosphate dehydrogenase decreased significantly in the group with higher exposure and could be the cause of the elevated concentrations of conjugated dienes.

It is possible to conclude that lead interferes with carbohydrate metabolism, but compensatory mechanisms seem to be efficient, as glucose homeostasis in lead-exposed workers was not disturbed.

Function of the liver and bile ducts in humans exposed to lead

Lead is very common in the environment, and it is therefore important to characterize its possible adverse health effects. The aim of this study was to evaluate the impact of lead exposure on selected functions of the liver and bile ducts in people who are chronically exposed to the metal because of their occupations. To provide this information, the activity of specific enzymes and the bilirubin concentration were determined in blood serum, and morphological parameters of the liver and bile ducts were evaluated using the ultrasonic imaging method. Healthy male employees of a lead–zinc processing facility ( n = 145) who were occupationally exposed to lead were divided into two subgroups as a function of the lead concentrations in blood (PbB): low lead exposure (PbB = 20–35 μg/dl; n = 57) and high lead exposure (PbB = 35–60 μg/dl; n = 88). Human exposure to lead compounds was found to cause liver enlargement and to activate inflammatory reactions with the characteristics of moderate cholestasis within the bile ducts, while no characteristics of necrotic damage of hepatic cells were noted. It seems that lipid peroxidation can be one of the toxic mechanisms of lead which induce moderate cholestasis. The effects depend on the extent of the lead exposure and were greater in subjects with higher exposure levels, particularly subjects with PbB values greater than 35 μg/dl.