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Zinc (Zn) is one of the most important trace elements in the body and it is essential as a catalytic, structural and regulatory ion. It is involved in homeostasis, in immune responses, in oxidative stress, in apoptosis and in ageing. Zinc-binding proteins (metallothioneins, MTs), are protective in situations of stress and in situations of exposure to toxic metals, infections and low Zn nutrition. Metallothioneins play a key role in Zn-related cell homeostasis due to their high affinity for Zn, which is in turn relevant against oxidative stress and immune responses, including natural killer (NK) cell activity and ageing, since NK activity and Zn ion bioavailability decrease in ageing. Physiological supplementation of Zn in ageing and in age-related degenerative diseases corrects immune defects, reduces infection relapse and prevents ageing. Zinc is not stored in the body and excess intakes result in reduced absorption and increased excretion. Nevertheless, there are cases of acute and chronic Zn poisoning.

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Endocrine system is one of the most sensitive communication networks of the human body which influences all aspects of human health and well-being, including reproductive potential, cognitive functions, thyroid and metabolism, digestion and hormonal balance. In recent years basic laboratory research has been focused on the potential relationship between environmental contaminants and cellular endocrine function. Environmental contaminants are ubiquitous in the environment, alter endocrine physiology and produce endocrine disruption without acting as classic toxicants. These endocrine disruptors (EDCs) are lipophilic and stored for long periods of time in the adipose tissue. Maternal exposure to EDCs during pregnancy and lactation has as a result the exposure of the fetus and neonate through placenta and breast milk. It has been recognized that human milk is the best natural food for neonates providing immunologic, developmental and practical advantages throughout childhood. However, contamination of human milk by the presence of environmental toxicants is widespread through the past decades due to inadequately controlled pollution. Persistent pesticides, chemical solvents and others tend to invade slowly the environment, to bioaccumulate in the food chain and to have long half-lives in animals and humans. During the past fifteen years, the scientific interest has been focused on xenoestrogens, i.e.,environmental chemicals with estrogen disrupting activity. Certain adverse health and reproductive outcomes are attributed to these chemicals in wildlife, in laboratory animals, as well as in humans. Although most toxic agents are hazardous in high doses, the human health risks associated with EDCs concern exposure to low doses. The human health risks that may be associated with these low-level but constant exposures are still largely unknown and highly controversial. In this paper, we review available data on environmental chemicals present in breast milk that may affect child health through breastfeeding. Specifically, we focused on the breast-feeding pharmacokinetic aspects related to infant exposure of chemical pollutants that have estrogen and antiandrogen activities, such as environmental estrogen disruptors or xenoestrogens.

The interpretation of toxicological findings is critical for the thorough investigation of the use and abuse of psychoactive substances. A positive analytical result for a sample taken could usually result in criminal proceedings and a punitive outcome for the defendant whose sample was analysed. The detection of markers of illicit opiate misuse is important both in the management of substance misuse and in the postmortem identification of illicit opiate use. The aim of this study was to emphasise the role of opiate biomarkers available at the laboratory and in the clinical environment. Urine remains the biological tool of choice for qualitative detection of illicit drug use in a clinical setting, while quantitative accuracy remains strictly the domain of blood. Accurate interpretation of the screening tests within a clinical setting alongside other relevant information remains the key to the usefulness of any test. Moreover, the finding of a morphine/codeine concentration ratio in blood exceeding unity is a strong evidence that the person had used heroin, as opposed to having taken a prescription analgesic drug containing codeine.