Teresa I. Fortoul

DNA damage in leukocytes and buccal and nasal epithelial cells of individuals exposed to air pollution in Mexico City.

There is an increased interest in using biological markers to monitor individuals for possible exposure to environmental toxicants. Test systems which permit the sensitive detection of DNA damage and DNA repair are critically important in such studies. The single cell gel electrophoresis (SCG) assay is a rapid and a sensitive method for the evaluation of DNA damage at the single cell level, providing information on the occurrence of DNA single‐strand breaks and alkali labile sites using alkaline conditions. In this study, the differences in the basal level of DNA damage between young adults from the south (exposed principally to high levels of ozone) and young adults from the north (exposed principally to hydrocarbons and particles) of Mexico City were investigated by the SCG assay using three different cell types (leukocytes and nasal and buccal epithelial cells). We found an increased DNA migration in blood leukocytes and nasal cells from individuals who live in the southern part of the city compared to those living in the northern part; however, no differences were observed for buccal epithelial cells. These results show the feasability of using the SCG assay to evaluate DNA damage in different tissues and its great potential for use in the monitoring of humans potentially exposed to genotoxic pollutants. Environ. Mol. Mutagen. 30:147–152, 1997

Follicular bronchiolitis in association with connective tissue diseases.

Eleven patients with connective tissue diseases were found to have bronchiolar lesions associated with minimal or no alveolar septal thickening. Seven of these patients had rheumatoid arthritis, 3 had Sjögren’s syndrome, and 1 had ankylosing spondylitis.Radiographic studies showed an interstitial pattern in all patients. The patients were nonsmokers and received no treatment prior to biopsy. All lung biopsy specimens showed inflammatory bronchiolar lesions which consisted of bronchiolar and peribronchiolar lymphocytic infiltrates (follicular bronchiolitis). The bronchiolar lesion has been reported previously in patients with connective tissue diseases treated with D-penicillamine; whether it represents a component of the systemic disease or a lack of effect of the therapeutic agent had not been established. The present study shows that several connective tissue diseases can be associated with inflammatory bronchiolar lesions.

Memory deterioration in an oxidative stress model and its correlation with cytological changes on rat hippocampus CA1

Exposure to ozone results in an increased production of free radicals which causes oxidative stress. The purpose of this study was to determine the effects of ozone exposure on memory and its correlation with the cytology of the hippocampus. Twenty-four male Wistar rats were exposed to 1 ppm (parts per million) ozone for 4 h in a closed chamber. Control group was exposed to flowing air. After ozone exposure, the rats were given long-term (24 h) memory training which consists of a passive avoidance conditioning. After that the animals were perfused and the brains were placed in the Golgi stain. The analysis consisted in counting the dendritic spines in five secondary and five tertiary dendrites of each of the 20 pyramidal neurons of hippocampus CA1 analyzed. Our results showed alterations on long-term memory and a significant reduction of dendritic spines, and provided evidence that this deterioration in memory is probably due to the reduction in spine density in the pyramidal neurons of hippocampus.

Vanadium in Ambient Air: Concentrations in Lung Tissue from Autopsies of Mexico City Residents in the 1960s and 1990s

Abstract Vanadium concentrations in lung tissue were determined by atomic absorption spectrometry from autopsy specimens taken from residents of Mexico City during the 1960s and 1990s (20 males and 19 females, and 30 males and 18 females, respectively). Samples from the 1990s had significantly increased mean vanadium concentrations (mean ± standard deviation: 1.36 ± 0.08), compared with those from the 1960s (1.04 ± 0.05). Concentrations were not correlated with gender, smoking habit, age, cause of death, or occupation. These findings suggest that vanadium in ambient air is increasing and it represents a potential health hazard for Mexico City residents. Air pollution monitoring efforts should include vanadium concentrations in suspended particles to follow-up the findings reported herein. Researchers need to acquire a better knowledge of the levels of airborne vanadium exposure at which risk to human health occurs.

Claudin-6, 7, or 9 Overexpression in the Human Gastric Adenocarcinoma Cell Line AGS Increases Its Invasiveness, Migration, and Proliferation Rate

Altered claudin expression is related to metastatic potential, poor prognosis, or tumor recurrence. We analyzed if the overexpression of claudin-6, claudin-7, or claudin-9 in AGS cells altered cell motility, invasiveness, or proliferation rate. Claudin-7, claudin-9, and claudin-6 enhanced their invasive potential by 3.4-fold, 1.6-fold, and 2.0-fold, respectively. Claudin-6 and claudin-9 enhanced cell migration, while the proliferation rate of claudin-6-, claudin-7-, and claudin-9-transfected cells increased by 12.7%, 9.0%, and 13.3%, respectively. Claudin-7 and claudin-9 overexpression increased claudin-1 and zonula occludens-1 levels. In summary, individual increased expression of claudin-6, claudin-7, or claudin-9 is sufficient to enhance tumorigenic properties of a gastric adenocarcinoma cell line.

Evaluation of DNA damage in exfoliated tear duct epithelial cells from individuals exposed to air pollution assessed by single cell gel electrophoresis assay

The search for relevant target cells for human monitoring purposes has increased during the last few years. Cells such as sperm, buccal or nasal and gastric epithelium are being used. In this study, we report the use of exfoliated tear duct epithelial cells as a potential material for human biomonitoring studies, since these cells are a target for environmental pollutants. We employed the alkaline single cell gel electrophoresis (SCGE) assay to evaluate for differences in the basal level of DNA damage between young adults from the south (exposed mainly to high levels of ozone) and from the north (exposed principally to hydrocarbons) regions of Mexico City. We found an increase in DNA migration in tear duct epithelial cells from individuals who live in the southern part of the city compared to those living in the northern part. Moreover, young people who live in the southwest part of the city with the highest values of ozone presented the highest values of DNA damage. These results show the feasibility of using exfoliated tear duct epithelial cells in human biomonitoring studies.

Ultrastructural modifications in the mitochondrion of mouse Sertoli cells after inhalation of lead, cadmium or lead-cadmium mixture.

CD-1 mice inhaled 0.01 M lead acetate, 0.006 M cadmium chloride or Pb-Cd mixture during 1h twice a week during 4 weeks. Testes were processed for transmission electron microscopic analysis. The percentage of damaged mitochondria was related to exposure time and the type of metal inhaled, noticing more damage when the mixture was administered. A dose-time relationship was found. Cadmium chloride caused the most severe mitochondrial alteration compared to lead acetate, whereas the mixture was more aggressive compared with each metal alone. Our results suggest that the changes in Sertoli cell could lead to a transformation process that may interfere with spermatogenesis.

Cadmium determination in Mexican-produced tobacco

Exposure to cadmium by inhalation or ingestion is dangerous for human health. This metal induces damage to the kidneys, the bones, the prostate, and the lungs. In the lungs, cadmium can produce cancer, emphysema, and fibrosis. It is well known that tobacco leaves are contaminated with cadmium, a metal that has been related to pulmonary damage. In this paper we report the concentration of cadmium in tobacco leaves and in cigarettes produced for domestic consumption. Fifty-five cigarettes of different brands, prices, and stocks were analyzed as well as 48 samples from four different types of tobacco. The average concentration of cadmium in cigarettes was 4.41 +/- 0.67 micrograms/g, and 2.65 +/- 0.99 micrograms/g for tobacco leaves; the content of cadmium was 2.8 +/- 0.4 micrograms/cigarette. It was estimated that a person that smokes 20 Mexican cigarettes per day can increase his (her) cadmium burden by 1.4 to 2.8 micrograms per day.

Morphologic alteration of the olfactory bulb after acute ozone exposure in rats

The interaction of ozone with some molecules results in an increased production of free radicals. The objective of this study was to identify whether acute ozone exposure to 1-1.5 ppm for 4 h, produced cytological and ultrastructural modifications in the olfactory bulb cells. The results showed that in rats exposed to ozone there was a significant loss of dendritic spines on primary and secondary dendrites of granule cells, whereas the control rats did not present such changes. Besides these exposed cells showed vacuolation of neuronal cytoplasm, swelling of Golgi apparatus and mitochondrion, dilation cisterns of the rough endoplasmic reticulum. These findings suggest that oxidative stress produced by ozone induces alterations in the granule layer of the olfactory bulb, which may be related to functional modifications.

Ependymal epithelium disruption after vanadium pentoxide inhalation. A mice experimental model.

The blood-brain barrier (BBB) protects the CNS against chemical insults. Regulation of blood-brain tissue exchange is accomplished by ependymal cells, which possess intercellular tight junctions. Loss of BBB function is an etiologic component of many neurological disorders. Vanadium (V) is a metalloid widely distributed in the environment and exerts potent toxic effects on a wide variety of biological systems. The current study examines the effects of Vanadium pentoxide (V2O5) inhalation in mice ependymal epithelium, through the analysis of the brain metal concentrations and the morphological modifications in the ependymal cells identified by scanning and transmission electron microscopy after 8 weeks of inhalation, in order to obtain a possible explanation about the mechanisms that V uses to enter and alter the CNS. Our results showed that V2O5 concentrations increase from the first week of study, stabilizing its values during the rest of the experiment. The morphological effects included cilia loss, cell sloughing and ependymal cell layer detachment. This damage can allow toxicants to modify the permeability of the epithelium and promote access of inflammatory mediators to the underlying neuronal tissue causing injury and neuronal death. Thus, understanding the mechanisms of BBB disruption would allow planning strategies to protect the brain from toxicants such as metals, which have increased in the atmosphere during the last decades and constitute an important health problem.