Lead poisoning has been recognized as a major public health risk, particularly in developing countries. Though various occupational and public health measures have been undertaken in order to control lead exposure, cases of lead poisoning are still reported. Exposure to lead produces various deleterious effects on the hematopoietic, renal, reproductive and central nervous system, mainly through increased oxidative stress. These alterations play a prominent role in disease manifestations. Modulation of cellular thiols for protection against reactive oxygen species (ROS) has been used as a therapeutic strategy against lead poisoning. N-acetylcysteine, α-lipoic acid, vitamin E, quercetin and a few herbal extracts show prophylaxis against the majority of lead mediated injury in both in vitro and in vivo studies. This review provides a comprehensive account of recent updates describing health effects of lead exposure, relevant biomarkers and mechanisms involved in lead toxicity. It also updates the readers about recent advances in chelation therapy and newer therapeutic strategies, like nanoencapsulation, to treat lead induced toxic manifestations.

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Toxicity of lead: A review with recent updates.

‘Water is life,’ so central to human life, yet over one billion people across the world have no access to safe drinking water. Of late, there has been increasing global attention focused on resolving water quality problems especially in developing countries, as the lack of access to clean water denies the most essential of all rights, the right to life. The latest estimates suggest that around 200 million people, from among 25 nations the world over, are under the dreadful fate of fluorosis. India and China, the two most populous countries of the world, are the worst affected. India is plagued with numerous water quality problems due to prolific contaminants mainly of geogenic origin and fluoride stands first among them. The weathering of primary rocks and leaching of fluoride-containing minerals in soils yield fluoride rich groundwater in India which is generally associated with low calcium content and high bicarbonate ions. The unfettered ground water tapping exacerbates the failure of drinking water so...

Fluoride in Drinking Water: A Review on the Status and Stress Effects

Minerals are inorganic nutrients, usually required in small amounts from less than 1 to 2500 mg per day, depending on the mineral. As with vitamins and other essential food nutrients, mineral requirements vary with animal species. For example, humans and other vertebrates need large amounts of calcium for construction and maintenance of bone and normal function of nerves and muscles. Phosphorus is an important constituent of adenosine triphosphate (ATP) and nucleic acid and is also essential for acid-base balance, bone and tooth formation. Red blood cells can not function properly without iron in haemoglobin, the oxygen-carrying pigment of red blood cells. Iron is also an important component of the cytochromes that function in cellular respiration. Magnesium, copper, selenium, zinc, iron, manganese and molybdenum are important co-factors found in the structure of certain enzymes and are indispensable in numerous biochemical pathways. Vertebrates need iodine to make thyroid hormones. Sodium, potassium and chlorine are important in the maintenance of osmotic balance between cells and the interstitial fluid. Magnesium is an important component of chlorophyll in plants. The interactions between nutrition and diseases, nutrition and drug metabolism have been reported. Excessive intake of some minerals can upset homeostatic balance and cause toxic side effects. For example, excess sodium intake is associated with high blood pressure and excess iron can cause liver damage. Also, severe shortages or self-prescribed minerals can alter the delicate balance in body functions that promotes health. The knowledge of the biochemistry of the mineral elements is also essential because individuals suffering from a chronic illness or taking medications that affect the body’s use of specific nutrients need to be enlightened. The aim of this paper is to review the biochemical functions and the importance of the mineral elements in health and disease conditions of humans, animals and plants as this will assist in the prevention of nutrition-related diseases and maintenance of good health for humans and animals that depend on plants for food. This paper could also serve as a ready source of literature review for researchers involved in nutritional sciences.

	 

	Key words: Mineral elements, humans, animals, plants, nutrition.

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The importance of mineral elements for humans, domestic animals and plants: A review

Exposure to heavy metals is a common phenomenon due to their environmental pervasiveness. Metal intoxication particularly neurotoxicity, genotoxicity, or carcinogenicity is widely known. This review summarizes our current understanding about the mechanism by which metalloids or heavy metals (particularly arsenic, lead, cadmium and mercury) induce their toxic effects. The unifying factor in determining toxicity and carcinogenicity for all these metals is the generation of reactive oxygen and nitrogen species. The toxic manifestations of these metals are caused primarily due to imbalance between pro-oxidant and antioxidant homeostasis which is termed as oxidative stress. Besides these metals have high affinity for thiol groups containing enzymes and proteins, which are responsible for normal cellular defense mechanism. Long term exposure to these metals could lead to apoptosis. Signaling components affected by metals include growth factor receptors, G-proteins, MAP kinases and transcription factors. Chelation therapy with chelating agents like calcium disodium ethylenediamine tetra acetic acid (CaNa(2)EDTA), British Anti Lewisite (BAL), sodium 2,3-dimercaptopropane 1-sulfonate (DMPS), meso 2,3-dimercaptosuccinic acid (DMSA) etc., is considered to be the best known treatment against metal poisoning. Despite many years of research we are still far away from effective treatment against toxicity caused due to exposure to heavy metals/metalloids. The treatment with these chelating agents is compromised with number of serious side-effects. Studies show that supplementation of antioxidants along-with a chelating agent prove to be a better treatment regimen than monotherapy with chelating agents. This review attempts a comprehensive account of recent developments in the research on heavy metal poisoning particularly the role of oxidative stress/free radicals in the toxic manifestation, an update about the recent strategies for the treatment with chelating agents and a possible beneficial role of antioxidants supplementation to achieve the optimum effects. We have selected only arsenic, lead, mercury and cadmium for this article keeping in view current concerns and literature available.

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Heavy metal induced oxidative stress & its possible reversal by chelation therapy.

In aerobic organisms, oxygen is essential for efficient energy production but paradoxically, produces chronic toxic stress in cells. Diverse protective systems must exist to enable adaptation to oxidative environments. Oxidative stress (OS) results when production of reactive oxidative species (ROS) exceeds the capacity of cellular antioxidant defenses to remove these toxic species. Epidemiological and clinical studies have linked environmental factors such as diet and lifestyle to cancer, diabetes, atherosclerosis, and neurodegenerative disorders. All of these conditions, as well as the aging process, are associated with OS due to elevation of ROS or insufficient ROS detoxification. Many environmental pollutants engage signaling pathways that are activated in response to OS. The same sequences of events are also associated with the etiology and early pathology of many chronic diseases. Investigations of oxidative responses in different in vivo models suggest that, in complex organisms such as mammals, organs and tissues contain distinct antioxidant systems, and this may form the basis for differential susceptibility to environmental toxic agents Thus, understanding the pathways leading to the induction of antioxidant responses will enable development of strategies to protect against oxidative damage. We shall review evidence of organ-specific antioxidant responses elicited by environmental pollutants in humans and animal models.

The role of antioxidants and antioxidant-related enzymes in protective responses to environmentally induced oxidative stress

Eight 6–9 month old calves, showing clinical signs of intermittent haemoglobinuria, even after treatment with an antipiroplasmal drug (4,4-diamidinodiazoaminobenzene diaceturate), were examined for oxidative damage to their erythrocytes and the presence of hemoprotozoa in blood smears. Four calves without signs of haemoglobinuria served as controls. The blood smears from three of the eight calves contained piroplasms for Theileria annulata. Irrespective of the presence of piroplasms in their blood smears, the calves with haemoglobinuria had significantly (p<0.01) lower haemoglobin concentrations (Hb) and packed cell volumes (PCV). The lipid peroxide level in the erythrocytes, but not in the plasma, of calves with red urine was significantly (p<0.05) higher than that for the controls. It is concluded that haemoglobinuria, irrespective of the presence of piroplasms in blood smears, is associated with oxidative stress to erythrocytes and peroxidation of polyunsaturated fatty acids of cell membrane.

Enhanced lipid peroxide levels in the erythrocytes of calves with haemoglobinuria.

In this experiment thirty rats were exposed to 0 (Gr. I, healthy controls) or 10 ppm arsenic (sodium arsenite) through drinking water ad lib for eight weeks after dividing them into five groups of six rats each. Rats in Gr. III, IV and V were administered a daily oral dose of cysteine, methionine or ascorbic acid 25 mg/kg body mass respectively, while those in Gr. II served as the treated control. At the end of the experimental period oxidative stress indices viz. lipid peroxides level (LPO), superoxide dismutase (SOD) and catalase (CAT) activities were estimated in blood, liver and kidneys from sacrificed rats. Arsenic exposure resulted in a significant (P 0.05) effects on the body mass of rats of different groups over time. It is concluded from the present study that prophylactic co-administration of cysteine, methionine and ascorbic acid could provide tissue specific protection from oxidative injury during sub-chronic exposure to arsenic.

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Role of co-administration of antioxidants in prevention of oxidative injury following sub-chronic exposure to arsenic in rats

Science of the Total Environment

Crossbred calves (15), aged one month, Were given 7.5 mg oHead acetate/ kg body weight by oral route daily for.28 days to study the sequential effects of lead-exposure on trace minerals inblood. Control calves (5) were given no treatment Sequential alterations in the trace mineral profile in blood and biochemical parameters in serum were monitored at weekly interval during exposure to lead. Serial blllod sampling was carried out before exposure, to lead (day 0) and thereafter at weekly intetyal for 4 weeks. Haematobiochemical changes included decreased haemoglobin (Hp) and increased serum urea nitrogen. Increase in blood lead concentration in lead-exposed calves was associated with a decrease in blood copper and an increase in cobalt concentration. Blood zinc concentrationinthe lead-exposed ariimals on day iand therafter, was significantly higher than that of day 0 value. However, theS!i changes were not sufficient enough to become statistically different from respective control values. Similarly, significant changes in serum protein and glohulm levels wete tecorded on day 21 and 28, compared to respective control values. It is condudedthat micronutrIent profile and Hb level In the blood are altered by exposure to lead even in absence of overt clinical signs.

Trace minerals in blood of young calves during exposure to lead

In this present study, blood samples were collected from 10 clinically healthy and 20 adult cattle naturally infected with Trypanosomes. Blood samples were evaluated for haematological and biochemical as well as erythrocytic oxidative stress marker for both infected and control groups. The results of the study revealed substantial decrease (%) in levels of Hb (42%), PCV (39%), total protein (46%), albumin (39%), globulin (44.6%), blood glucose (46%), SOD (57.7%), CAT (62%) and increase (%) in LPO (295%), AST (70%) and ALT (4.5%) in infected cattle compared to healthy animals. Oxidative stress marker enzymes like SOD and Catalase decreased two times in infected group whereas Lipid peroxidase (LPO) increased nearly four times in infected group as compared to healthy group. Thus enhanced erythrocytic oxidation and reduction of haematological indices suggests that, trypanosome affected cattle undergoes severe oxidative stress and resultant anaemia.

https://www.entomoljournal.com/archives/2017/vol5issue6/PartJ/5-5-277-430.pdf

Ramesh Chandra Patra

Papers

Enhanced lipid peroxide levels in the erythrocytes of calves with haemoglobinuria.

Role of co-administration of antioxidants in prevention of oxidative injury following sub-chronic exposure to arsenic in rats

Science of the Total Environment

Trace minerals in blood of young calves during exposure to lead

Trypanosomiasis induced oxidative stress and hemato-biochemical alteration in cattle