Research Database –
International Updates

Environmental Toxicology

Issue 93

RAMANATHAN and colleagues, Department of Medical Biochemistry, Dr AL Mudaliar Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India, have investigated the effects of vitamins C and E on arsenic-induced oxidative stress.
Background: Arsenic is an ubiquitous element in the environment that causes an oxidative burst in exposed individuals and can thereby lead to tissue damage. Antioxidants have long been known to reduce the free- radical mediated effects of oxidative stress. The present study was designed to determine whether supplementation with vitamins C and E to arsenic-intoxicated rats could protect against the oxidative stress caused by the metal.
Methods: Rats were poisoned with low levels of arsenic (100 ppm in drinking water) and supplemented with 400 mg/kg of body weight of alpha-tocopherol (vitamin E) and 200 mg/kg of body weight of ascorbic acid (vitamin C) per day. Biochemical parameters were measured.
Results: The arsenic treated rats showed elevated lipid peroxidation and decreased levels of antioxidants, all signs of oxidative stress. Administration of vitamins C and E resulted in a decrease of lipid peroxides and enhanced levels of sulfhydryls, reduced glutathione, and the activities of superoxide dismutase, catalase, and a number of related enzymes involved in the counteraction of oxidative stress, to near normal.
Conclusions: The results suggest that vitamins C and E prevent lipid peroxidation and protect the antioxidant system in arsenic-poisoned rats.
Ramanathan K, Balakumar BS, Panneerselvam C. Effects of ascorbic acid and alpha-tocopherol on arsenic-induced oxidative stress. Human and Experimental Toxicology 21 (12): 675-680, Dec 2002.

Issue 77

SEIDEL, Institute for Occupational, Social and Environmental Medicine, University of Ulm, Ulm, Germany, hans-joachim.seidel@medizin.uni-ulm.de, reviewed (50 references) how environmental medicine has developed as a new field of medical specialization in Germany.
Discussion: Increasing public and professional concern about how environmental factors may affect health has led to the formation of new scientific societies to address these issues and to assessments by independent ‘critical’ physicians. Initially, centres for environmental medicine, attached to research institutions or in association with public health services, were set up to assess and treat individuals believed or suspected to be suffering from environmentally related health problems or conditions. Subsequently, medical professional organizations, particularly the German General Medical Council, have worked together to develop a specific training programme for doctors, in the field of environmental medicine. This training includes a 200-hour course, and to date 3,000 doctors have completed the course and passed its qualifying exam. Most doctors have been from the public health service and from occupational medicine, while few doctors in primary care (GPs) have undergone the training. The author comments on the lack of meaningful research studies conducted on patients with ‘environmentally related’ health problems. He reviews common conditions thought to be environmentally related and summarizes some of the main research activities on environmental medicine that have been or are being conducted in Germany. The author also describes problems of designing and conducting studies in this area, such as accounting systems, and the diagnosis and treatment of patients with multiple chemical sensitivities (MCS). He reports on a new coordinated research programme on MCS that is now underway.
Seidel HJ. Environmental medicine in Germany – a review. Environmental Health Perspectives 110 (Suppl 1): 113-8. Feb 2002.

Issue 72

LANDRIGAN, Departments of Community-Preventive Medicine and Pediatrics, Mount Sinai School of Medicine, New York, NY, USA, reviewed (43 references) the growth in importance over the last half century of environmental causes and factors in childhood diseases.
Discussion: Environmental paediatrics is an area of paediatric medicine that has come a long way in the last 50 years. It has risen to importance in parallel with two developments: 1) the conquest in the industrialized nations of the major infectious diseases and their replacement by chronic conditions such as asthma, cancer, developmental disabilities and birth defects as the primary causes of illness and death in children; and 2) the growing recognition that chemicals in the environment are responsible, at least in part, for these changes in patterns of disease. The challenge now to environmental paediatrics is to better understand the impact of chemical substances on the patterns of health and disease in children and to design evidence-based approaches to the treatment and prevention of childhood disease of environmental origin.
Landrigan PJ. Children’s environmental health. Lessons from the past and prospects for the future. Pediatric Clinics of North America 48 (5): 1319-30. Oct 2001.

GITTERMAN and BEARER, Departments of Pediatrics and Public Health, George Washington University Schools of Medicine and Public Health and Health Services, General and Community Pediatrics, Children’s National Medical Center, Washington DC, USA, bgitterm@cnmc.org, reviewed (73 references) literature pertaining to differences (compared with adults) in the ways children respond to environmental toxic substances.
Discussion: Children cannot be considered ‘little adults’ in the field of environmental medicine. There are differences in exposures, pathways of absorption, tissue distribution, ability to biotransform or eliminate chemicals from the body, and responses to chemicals and radiation. The differences vary with the developmental stages of the child. All children respond differently to environmental toxicants. Knowledge, although rapidly increasing, is still incomplete regarding the impact of the environment on children. For health care providers, prevention is an ally but must be approached differently at each stage of a child’s life.
Gitterman BA, Bearer CF. A developmental approach to pediatric environmental health. Pediatric Clinics of North America 48 (5): 1071-83. Oct 2001.
Comment: When historians look back on the 20th and 21st centuries, it is likely that environmental medicine will figure largely in the epidemics of cancer currently affecting about a third of the population of the developed world. Hopefully we won’t all be dead by that time!

Issue 31

HELEN and VIJAYAMMAL, Department of Biochemistry, University of Kerala, Thiruvananthapuram, India investigated whether oxidative damage in rat liver caused by exposure to cigarette smoke is effectively counterracted with vitamin C.
METHODS: The authors assessed liver antioxidants vitamins A, C and E, liver scavenging enzymes and lipid peroxide products in rats exposed to cigarette smoke given 200 mg (100 g/l body weight) vitamin C for 90 days.
RESULTS: Malondialdehyde (MDA), conjugated dienes, hydroperoxides and free fatty acids (FFA) were significantly increased in the liver of rats exposed to smoke. Superoxide dismutase and catalase activity, and concentrations of vitamins C and E were significantly lower compared with controls, and vitamin A concentration, glutathione (GSH) and glutathione peroxidase (GSH Pxase) activity were enhanced. Supplementation with vitamin C in rats exposed to cigarette smoke resulted in increased resistance to lipid peroxidation and increased activity of scavenging enzymes, and normalisation of GSH, vitamin C and free fatty acids levels.
CONCLUSIONS: The results of this study suggest that supplementation with a mega dose of vitamin C is able to protect the liver from oxidant damage caused by cigarette smoke.
Helen A and Vijayammal PL. Vitamin C supplementation on hepatic oxidative stress induced by cigarette smoke. J Appl Toxicol. 17(5): 289-95. Sep-Oct 1997.

ELLINGSEN and colleagues, Department of Occupational and Environmental Medicine, Telemark Central Hospital, Skien Norway investigated the possible interactions of mercury, cadmium and selenium in humans.
METHODS: The authors conducted a cross-sectional study of 130 men, of whom 77 had previously been exposed to mercury vapour at an industrial plant. 61.5% of the participants were smokers 16.2% never smoked.
RESULTS: Compared to those men who had never smoked, the concentration of selenium in blood (B-Se), was significantly lower in smoking men and the cadmium blood (B-Cd) concentration was significantly higher in all categories of current smokers. B-Se was negatively associated with B-Cd, whereas B-Cd was positively associated with current and previous smoking habits and negatively with B-Se and the cumulative dose of previous mercury vapour exposure. B-Se was also negatively associated with B-Cd in those who never smoked.
CONCLUSIONS: These results suggest that cadmium exerts a depressive effect upon blood selenium, while smoking alone does not operate as a true predictor for this effect. Additionally, previous exposure to mercury modifies blood cadmium concentration.
Ellingsen DG et al. Cadmium and selenium in blood and urine related to smoking habits and previous exposure to mercury vapour. J Appl Toxicol 17(5): 337-43. Sep-Oct 1997.
COMMENTS: Much illness in our society may emanate from environmental and chemical sources. It is about time that measures such as supplemental vitamin C or other types of dietary supplements are properly investigated, because it is impossible to live in a “pure” environment, either internally or externally.