Search

Epidemiologic studies indicate that prolonged exposure to high pollution levels is associated with increased risk of cancer, especially lung cancer. However, under conditions of moderate or low air pollution, epidemiologic evidence does not permit reliable conclusions. Biomarker-based population studies may serve as complementary tools providing a better understanding of the relative contribution of ambient atmospheric pollution to the overall genotoxic burden suffered by city dwellers. However, past efforts to apply biomarkers to studies of low levels exposure to urban air pollution have given inconclusive results, partly because of the absence of adequate data on personal exposure, covering a time-window which is appropriate for the biomarkers being examined, as well as a battery of biomarkers reflecting different stages of the carcinogenic process. In the present paper, the potential of biomarker-based population studies to aid the assessment of the genotoxic and carcinogenic effects of urban air pollution is reviewed by reference to the achievements and limitations of earlier reported studies. The design and methodology adopted in a recently completed large-scale population study, carried out in the context of the European Union Environment and Climate Programme, known by the short name of AULIS project, is discussed and descriptive statistics of the main findings of the project are presented. These findings indicate that for cohorts suffering moderate-to-low exposures to airborne particulate-bound polycyclic aromatic hydrocarbons (PAHs), no simple correlation with biomarkers of genotoxicity existed and suggest that additional factors made a significant contribution to the overall genotoxic burden.

It is envisaged that flow cytometric analysis of lymphocyte subsets in cord blood may be used as a biomarker for effects on the immune system of exposure to environmental factors. In order to investigate the possible application of this parameter, we first studied the effects of other factors that may influence the outcome of subset analysis in cord blood. FACS analysis was performed in 112 pairs of umbilical cord blood and of peripheral maternal blood sampled at labour. Whereas in maternal blood no statistically significant effects of medication during labour on T lymphocyte numbers and NK cells were found, in oxytocin- and in oxytocin and prostaglandin-treated mothers B cell numbers showed a statistically significant increase. In cord blood, the course of labour and/or medication during labour were identified as the most important factors determining distribution of major lymphocyte subsets. In cord blood after deliveries without medication or after neuroplegic analgesia (NPA), the mean percentage of cord blood T lymphocytes (CD3 + ) was highest (59%) and that of NK lymphocytes (CD3 ± /CD16 + 56 + ) lowest (20%). The mean percentage of T lymphocytes was significantly lower (52%) and that of NK lymphocytes higher (28%) in cord blood where deliveries were done under NPA in combination with infusion of oxytocin. The combination of NPA with oxytocin and induction of labour by prostaglandin E2 led to a further reduction of T lymphocytes and an increase of NK cells (39% and 38% respectively). The changes in ratio of T and NK lymphocytes were due both to decreasing absolute counts of T lymphocytes and increasing counts of NK lymphocytes. Thus, the effects of labour and/or medication during labour must be taken into account when this parameter is applied as a potential biomarker of effects of environmental factors on the immune system.

Objectives: To assess in venous cord blood the distribution of major lymphocyte subsets according to pH and medications used during labor. Design and methods: Venous cord blood was sampled immediately after labor from 70 newborns (35 males and 35 females) delivered vaginally. Lymphocytes were immunophenotyped by flow cytometry and pH was measured using the AVL 900 automated blood gas analysis system. Data on birth weight, gestational age at delivery, length of labor, presence of stained amniotic fluid, medications used during labor, maternal risk factors, age and parity were collected. Results: The percentage of T lymphocytes decreased while the percentage of NK lymphocytes increased with decreasing pH over the whole range of pH values. The proportions of T and NK lymphocytes were associated with the administration of neuroplegics, spasmolytics or dihydroergotoxin in the first stage of labor. Conclusions: Cord blood pH and labor-associated variables should be taken into account to adequately interpret the profile of major lymphocyte subsets as a marker of the effect of different prenatal factors on the immune system of neonates.

It has long been hypothesized that schizophrenia may be related to a specific injury of genetic material. There is some evidence of chromosomal abnormalities (DeLisi et al. 1988). Another study examined the repair defects seen in schizophrenic patients when their lymphocytes were treated with 4-nitroquinoline or gamma-radiation (Zasukhina 1987). However, no significant DNA-repair defect was observed by Magin et al. (1991).