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THE EFFECT OF CALCIUM TAINTED WATER ON CADMIUM INDUCED LIVER DAMAGE


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ABSTRACT

Cadmium is recognize has a toxicant to both human and it’s environment and recent investigations have shown its level of toxicity in association in liver damage.  The aim of study is to determine the effect of calcium tainted water on cadmium induced liver damage  have been examine in this studies, 20 female wistar rat were used in this study the rats divided into four groups each containing 5 rats per group . The group one was maintained on normal feed and water only, the group 2 were exposed to cadmium only while the group three were exposed to calcium only and the group four were exposed simultaneously to cadmium and calcium. Each of the animal was given treatment based on their body weight (0.9 mg per kg body weight). The treatments were administered to the animals once a day for two weeks. At the end of two weeks the animals were sacrificed and the following biochemical markers were measured; Alkaline phosphatase, total protein, alanine amino transferase, total bilirubin and direct bilirubin.  All the biochemical markers were negatively affected by cadmium with exception to Albumin and total protein. The study reveal that cadmium has the potential to induce hepatotoxicity and calcium tainted water offer little ameliorating affect to cadmium induce liver damage.

 

 

TABLE OF CONTENTS

Cover page

Certification……………………………………………………………i

Dedication……………………………………………………………..ii

Acknowledgement…………………………………………………….iii

Table of contents………………………………………………………iv

Abstracts………………………………………………………………vii

CHAPTER ONE

Introduction and literature review…………………………………….1

Cadmium………………………………………………………………3

Physical and chemical properties……………………………………..4

Occurance………………………………………………………………5

Biological role………………………………………………………….6

Cadmium poisoning……………………………………………………7

Calcium………………………………………………………………..11

Calcium compound……………………………………………………12

Nutrition ………………………………………………………………14

Bone health…………………………………………………………….16

Cardiovascular impact…………………………………………………16

Hazard and toxicity……………………………………………………….17

Hard water …………………………………………………………………18

Sources of hardness ……………………………………………………….18

Temporary hardness………………………………………………………..19

Permanent hardness………………………………………………………..20

Effect of hard water…………………………………………………………21

Health consideration………………………………………………………22

The liver…………………………………………………………………...23

Anatomy of the liver……………………………………………………..24

Diseases of the liver………………………………………………………29

Liver function test………………………………………………………30

CHAPTER TWO

Materials and methods…………………………………………………35

Materials……………………………………………………………….35

Animals……………………………………………………………….36

Preparation of contaminated water………………………………….36

Treatment of animal…………………………………………………37

Preparation of seral sample…………………………………………..37

Preparation of tissue homogenates………………………………….37

Biochemical analyses………………………………………………….38

CHAPTER THREE

Results………………………………………………………………….46

CHAPTER FOUR

Discussion……………………………………………………………….53

Conclussion……………………………………………………………..54

References ……………………………………………………………...55

Appendix i………………………………………………………………66

Appendix ii……………………………………………………………..68

Appendix iii…………………………………………………………… 70

Appendix iv…………………………………………………………….75

Appendix v……………………………………………………………..79

 

 

CHAPTER ONE

1.0     INTRODUCTION AND LITERATURE REVIEW

Heavy metals are toxic agent. They are toxic to humans and animals. Heavy metals which establishes toxic actions to humans include; cadmium (Stohs and Bagchi,1995), lead ( Ferner, 2001) and mercury (Hawkes, 1997). Each of these has been studied   in isolation for toxicity (Huton and Symon, 1986; Nriagu and Pacyna, 1988; Nriagu, 1989). But, in the eco-system, be it air, atmosphere, land, and water where they occur, they do not exist in isolation. They occur in close association with other metal and non-metallic elemental pollutants. Among the metallic pollutant could be calcium, copper, zinc, magnesium, manganese, iron and others.  Metals are known to interact with one another. The interaction can bring two elements together in close proximity or it could cause out right displacement of one another. When ingested together in food and water, they antagonize each other. When it comes to intestinal and pulmonary absorption, it is therefore conceivable that the presence of other elements can the toxic potential of each of the heavy metals that have been studied in isolation.

          Eborge (1994) reported that warri river has an unacceptable high cadmium level, 0.3 mg cadmium per liter of water which was 60 folds above the maximum allowable level of 0.005 mg per liter. This report prompted our earlier studies on the hepato, nephro and gonadial toxicity of cadmium. In rats exposed to this high dose via water and diet, the diet was formulated with feed exposed to 0.3 mg cadmium per water. In the ambient water as protein source and the toxic effect investigated and reported (Asagba and obi 2000; Asagba and Obi 2001; Obi and Ilori 2002; Asagba and Obi 2004a; Asagba and Obi 2004b; Asagba and Obi 2005).The study focus on cadmium without taking into consideration the fact that other metals were also present in the river water, and as such were co-consumed by the communities using the river water for cooking drinking and for other domestic purposes. Hence, it is desirable to know if the presence of other metals would enhance or diminish the toxic potential of cadmium or indeed if any other heavy metals such as lead that was mentioned above. Therefore, the aim of the present study was to re-examine the toxic potential of cadmium in the presence of other metals such as calcium and magnesium.

          The objectives set out to achieve were;

1.     Re-examination of toxicity of using established and those for liver toxicity namely; blood alanine amino transferase and aspartate amino transferase, alkaline phosphatase, bilirubin, albumin and total protein.

2.     Re-examine the status parameter in the absence of cadmium but in the presence of calcium or magnesium or both.

3.     Re-examine this parameters in the presence of cadmium, calcium and magnesium.

1.1     CADMIUM

Cadmium is a chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals. Cadmium and its congeners are not always considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate. Cadmium occurs as a minor component in most zinc ores and therefore is a byproduct of zinc production. It was used for a long time as a pigment and for corrosion-resistant plating on steel, whereas cadmium compounds were used to stabilize plastic. The use of cadmium is generally decreasing due to its toxicity (it is specifically listed in the European Restriction of Hazardous Substances (Morrow, 2010)) and the replacement of nickel-cadmium batteries with nickel-metal hydride and lithium-ion batteries. One of its few new uses is in cadmium telluride solar panels. Although cadmium has no known biological function in higher organisms, a cadmium-dependent carbonic anhydrase has been found in marine diatoms.

1.1.1  PHYSICAL PROPERTIES

Cadmium is a soft, malleable, ductile, bluish-white divalent metal. It is similar in many respects to zinc but forms complex compounds (Holleman et al., 1985). Unlike other metals, cadmium is resistant to corrosion and as a result it is used as a protective layer when deposited on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable; however, in its powdered form it may burn and release toxic fumes (CSEM, 2011).

1.1.2  CHEMICAL PROPERTIES

Although cadmium usually has an oxidation state of +2, it also exists in the +1 state. Cadmium and its congeners are not always considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states (Cotton, 1999). Cadmium burns in air to form brown amorphous cadmium oxide (CdO); the crystalline form of this compound is a dark red which changes color when heated, similar to zinc oxide. Hydrochloric acid, sulfuric acid and nitric acid dissolve cadmium by forming cadmium chloride (CdCl2), cadmium sulfate (CdSO4), or cadmium nitrate (Cd(NO3)2). The oxidation state +1 can be reached by dissolving cadmium in a mixture of cadmium chloride and aluminium chloride, forming the Cd22+ cation, which is similar to the Hg22+ cation in mercury(I) chloride (Holleman et al., 1985).

Cd + CdCl2 + 2 AlCl3 → Cd2(AlCl4)2

The structures of many cadmium complexes with nucleobases, amino acids and vitamins have been determined (Carballo et al., 2013).

1.1.3  OCCURRENCE


Cadmium metal

Cadmium makes up about 0.1 ppm of Earth's crust. Compared with the more abundant 65 ppm zinc, cadmium is rare (Wedepohl, 1995). No significant deposits of cadmium-containing ores are known. Greenockite (CdS), the only cadmium mineral of importance, is nearly always associated with sphalerite (ZnS). This association is caused by the geochemical similarity between zinc and cadmium which makes geological separation unlikely. As a consequence, cadmium is produced mainly as a byproduct from mining, smelting, and refining sulfidic ores of zinc, and to a lesser degree, lead and copper. Small amounts of cadmium, about 10% of consumption, are produced from secondary sources, mainly from dust generated by recycling iron and steel scrap. Production in the United States began in 1907, (Ayres et al., 2003) but it was not until after World War I that cadmium came into wide use (Plachy, 1998). One place where metallic cadmium can be found is the Vilyuy River basin in Siberia (Fthenakis, 2004).

Rocks mined to produce phosphate fertilizers contain varying amounts of cadmium, leading to a cadmium concentration of up to 300 mg/kg in the produced phosphate fertilizers and thus in the high cadmium content in agricultural soils (Grant and Shepperd , 2008). Coal can contain significant amounts of cadmium, which ends up mostly in the flue dust (Bettinelli et al., 1988).

1.1.4  BIOLOGICAL ROLE

Cadmium has no known useful role in higher organisms, (Hogan, 2010) but a cadmium-dependent carbonic anhydrase has been found in some marine diatoms (Lane et al., 2005). The diatoms live in environments with very low zinc concentrations and cadmium performs the function normally carried out by zinc in other anhydrases. The discovery was made using X-ray absorption fluorescence spectroscopy (XAFS) (Lane et al., 2000).

The highest concentration of cadmium has been found to be absorbed in the kidneys of humans, and up to about 30 mg of cadmium is commonly inhaled throughout childhood and adolescence (Perry et al., 1976). Cadmium can be used to block calcium channels in chicken neurons (Swandulla and Armstrong, 1989). Analytical methods for the determination of cadmium in biological samples have been reviewed (klorz et al., 2013).

1.1.5  ENVIRONMENT

The biogeochemistry of cadmium and its release to the environment has been the subject of review, as has the speciation of cadmium in the environment (Cullen et al., 2013).

1.1.6  CADMIUM POISONING

The bioinorganic aspects of cadmium toxicity have been reviewed (Maret et al., 2013).The most dangerous form of occupational exposure to cadmium is inhalation of fine dust and fumes, or ingestion of highly soluble cadmium compounds.  Inhalation of cadmium-containing fumes can result initially in metal fume fever but may progress to chemical pneumonitis, pulmonary edema, and death (Hayes, 2007). Cadmium is also an environmental hazard. Human exposures to environmental cadmium are primarily the result of fossil fuel combustion, phosphate fertilizers, natural sources, iron and steel production, cement production and related activities, nonferrous metals production, and municipal solid waste incineration.  Bread, root crops, and vegetables also contribute to the cadmium in modern populations (Mann, 2012). There have been a few instances of general population toxicity as the result of long-term exposure to cadmium in contaminated food and water, and research is ongoing regarding the estrogen mimicry that may induce breast cancer (Mann, 2012). In the decades leading up to World War II, mining operations contaminated the Jinzū River in Japan with cadmium and traces of other toxic metals. As a consequence, cadmium accumulated in the rice crops growing along the riverbanks downstream of the mines. Some members of the local agricultural communities consuming the contaminated rice developed itai-itai disease and renal abnormalities, including proteinuria and glucosuria (Nogawa et al., 2004).


Jinzū River area, which was contaminated with cadmium

The victims of this poisoning were almost exclusively post-menopausal women with low iron and other mineral body stores. Similar general population cadmium exposures in other parts of the world have not resulted in the same health problems because the populations maintained sufficient iron and other mineral levels. Thus, although cadmium is a major factor in the itai-itai disease in Japan, most researchers have concluded that it was one of several factors. Cadmium is one of six substances banned by the European Union's Restriction on Hazardous Substances (RoHS) directive, which bans certain hazardous substances in electrical and electronic equipment but allows for certain exemptions and exclusions from the scope of the law. The International Agency for Research on Cancer has classified cadmium and cadmium compounds as carcinogenic to humans. Although occupational exposure to cadmium is linked to lung and prostate cancer, there is still a substantial controversy about the carcinogenicity of cadmium in low, environmental exposure. Recent data from epidemiological studies suggest that intake of cadmium through diet associates to higher risk of endometrial, breast and prostate cancer as well as to osteoporosis in humans (Julin et al., 2012). A recent study has demonstrated that endometrial tissue is characterized by higher levels of cadmium in current and former smoking females (Rzymski et al., 2014). Although some epidemiological studies show a significant correlation between cadmium exposure and occurrence of disease conditions in human populations, a causative role for cadmium as the factor behind these effects remains yet to be shown. In order to prove a causative role, it will be important to define the molecular mechanisms through which cadmium in low exposure can cause adverse health effects. One hypothesis is that cadmium works as an endocrine disruptor because some experimental studies have shown that it can interact with different hormonal signaling pathways. For example, cadmium can bind to the estrogen receptor alpha, (Fechner et al., 2011) and affect signal transduction along the estrogen and MAPK signaling pathways at low doses (Ali et al., 2010).

Tobacco smoking is the most important single source of cadmium exposure in the general population. It has been estimated that about 10% of the cadmium content of a cigarette is inhaled through smoking. The absorption of cadmium from the lungs is much more effective than that from the gut, and as much as 50% of the cadmium inhaled via cigarette smoke may be absorbed (Friberg, 1983). On average, smokers have 4–5 times higher blood cadmium concentrations and 2–3 times higher kidney cadmium concentrations than non-smokers. Despite the high cadmium content in cigarette smoke, there seems to be little exposure to cadmium from passive smoking. No significant effect on blood cadmium concentrations has been detected in children exposed to environmental tobacco smoke.  In the non-smoking part of the population food is the biggest source of exposure to cadmium. High quantities of cadmium can be found for example in crustaceans, molluscs, offals, and algal products. However, due to the higher consumption the most significant contributors to the dietary cadmium exposure are grains, vegetables, and starchy roots and tubers. Cadmium exposure is a risk factor associated with early atherosclerosis and hypertension, which can both lead to cardiovascular disease (Jarup, 1998).

1.2     CALCIUM

Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust. Calcium is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate (Dickson and Goyet 1994). Calcium is essential for living organisms, in particular in cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bone, teeth and shells, calcium is the most abundant metal by mass in many animals.

 

1.2.1  CALCIUM COMPOUNDS

1.2.2   NUTRITION

Calcium is an important component of a healthy diet and a mineral necessary for life. The National Osteoporosis Foundation says, "Calcium plays an important role in building stronger, denser bones early in life and keeping bones strong and healthy later in life." Approximately 99 percent of the body's calcium is stored in the bones and teeth. The rest of the calcium in the body has other important uses, such as some exocytosis, especially neurotransmitter release, and muscle contraction. In the electrical conduction system of the heart, calcium replaces sodium as the mineral that depolarizes the cell, proliferating the action potential. In cardiac muscle, sodium influx commences an action potential, but during potassium efflux, the cardiac myocyte experiences calcium influx, prolonging the action potential and creating a plateau phase of dynamic equilibrium. Long-term calcium deficiency can lead to rickets and poor blood clotting and in case of a menopausal woman, it can lead to osteoporosis, in which the bone deteriorates and there is an increased risk of fractures. While a lifelong deficit can affect bone and tooth formation, over-retention can cause hypercalcemia (elevated levels of calcium in the blood), impaired kidney function and decreased absorption of other minerals (Catharine et al., 2011). Several sources suggest a correlation between high calcium intake (2000 mg per day, or twice the U.S. recommended daily allowance, equivalent to six or more glasses of milk per day) and prostate cancer (giovannucci et al., 1998).  Dairy products, such as milk and cheese, are a well-known source of calcium. Some individuals are allergic to dairy products and even more people, in particular those of non Indo-European descent, are lactose-intolerant, leaving them unable to consume non-fermented dairy products in quantities larger than about half a liter per serving. Others, such as vegans, avoid dairy products for ethical and health reasons. Many good vegetable sources of calcium exist, including seaweeds such as kelp, wakame and hijiki; nuts and seeds like almonds, hazelnuts, sesame, and pistachio; blackstrap molasses; beans (especially soy beans); figs; quinoa; okra; rutabaga; broccoli; dandelion leaves; and kale. In addition, several foods and drinks, such as orange juice, soy milk, tofu, breakfast cereals, and breads are often fortified with calcium. Numerous vegetables, notably spinach, chard and rhubarb have a high calcium content, but they may also contain varying amounts of oxalic acid that binds calcium and reduces its absorption. The same problem may to a degree affect the absorption of calcium from amaranth, collard greens, and chicory greens. This process may also be related to the generation of calcium oxalate.

An overlooked source of calcium is eggshell, which can be ground into a powder and mixed into food or a glass of water (Schaafsma et al., 2002). The calcium content of most foods can be found in the USDA National Nutrient Database.

1.2.3  BONE HEALTH

Calcium supplementation can have a small effect in improving bone mineral density. This is of no meaningful benefit to health in children, but in post-menopausal women the risk of vertebral fractures may be reduced (Shea et al., 2004).

1.2.4  CARDIOVASCULAR IMPACT

A study investigating the effects of personal calcium supplement use on cardiovascular risk in the Women’s Health Initiative Calcium/Vitamin D Supplementation Study (WHI CaD Study) found a modestly increased risk of cardiovascular events, particularly myocardial infarction in postmenopausal women. A broad recommendation of calcium/vitamin D supplements is therefore not warranted.  In contrast, the authors of a 2013 literature review concluded that the benefits of calcium supplementation, such as on bone health, appear to outweigh any risk calcium supplementation may theoretically pose to the cardiovascular health (Downing and Islam 2013).

1.2.5  HAZARDS AND TOXICITY

Compared with other metals, the calcium ion and most calcium compounds have low toxicity. This is not surprising given the very high natural abundance of calcium compounds in the environment and in organisms. Calcium poses few serious environmental problems, with kidney stones the most common side-effect in clinical studies. Acute calcium poisoning is rare, and difficult to achieve unless calcium compounds are administered intravenously. For example, the oral median lethal dose (LD50) for rats for calcium carbonate and calcium chloride are 6.45 and 1.4 g/kg, (Lewis, 1996) respectively.

Calcium metal is hazardous because of its sometimes-violent reactions with water and acids. Calcium metal is found in some drain cleaners, where it functions to generate heat and calcium hydroxide that saponifies the fats and liquefies the proteins (e.g., hair) that block drains. When swallowed calcium metal has the same effect on the mouth, esophagus and stomach, and can be fatal (Rumack, 2010).

 

1.3     HARD WATER

Hard water is water that has high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of calcium and magnesium-containing minerals such as limestone, chalk and dolomite. Hard drinking water is generally not harmful to one's health, (WHO, 2003) but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects.

1.3.1  SOURCES OF HARDNESS

Water's hardness is determined by the concentration of multivalent cations in the water. Multivalent cations are cations (positively charged metal complexes) with a charge greater than 1+. Usually, the cations have the charge of 2+. Common cations found in hard water include Ca2+ and Mg2+. These ions enter a water supply by leaching from minerals within an aquifer. Common calcium-containing minerals are calcite and gypsum. A common magnesium mineral is dolomite (which also contains calcium). Rainwater and distilled water are soft, because they contain few ions (Hermann, 2006).

The following equilibrium reaction describes the dissolving and formation of calcium carbonate :

CaCO3 (s) + CO2 (aq) + H2O (l) Ca2+ (aq) + 2HCO3 (aq)

The reaction can go in either direction. Rain containing dissolved carbon dioxide can react with calcium carbonate and carry calcium ions away with it. The calcium carbonate may be re-deposited as calcite as the carbon dioxide is lost to atmosphere, sometimes forming stalactites and stalagmites.

Calcium and magnesium ions can sometimes be removed by water softeners

1.3.2  TEMPORARY HARDNESS

Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate). When dissolved, these minerals yield calcium and magnesium cations (Ca2+, Mg2+) and carbonate and bicarbonate anions (CO32-, HCO3-). The presence of the metal cations makes the water hard. However, unlike the permanent hardness caused by sulfate and chloride compounds, this "temporary" hardness can be reduced either by boiling the water, or by the addition of lime (calcium hydroxide) through the softening process of lime softening, (Christian et al., 2005) Boiling promotes the formation of carbonate from the bicarbonate and precipitates calcium carbonate out of solution, leaving water that is softer upon cooling.

1.3.3  PERMANENT HARDNESS

Permanent hardness is hardness (mineral content) that cannot be removed by boiling. When this is the case, it is usually caused by the presence of calcium sulfate and/or magnesium sulfates in the water, which do not precipitate out as the temperature increases. Ions causing permanent hardness of water can be removed using a water softener, or ion exchange column.

Total Permanent Hardness = Calcium Hardness + Magnesium Hardness

The calcium and magnesium hardness is the concentration of calcium and magnesium ions expressed as equivalent of calcium carbonate. Total permanent water hardness expressed as equivalent of CaCO3 can be calculated with the following formula: Total Permanent Hardness

(CaCO3) = 2.5(Ca2+) + 4.1(Mg2+).

1.3.4  EFFECTS OF HARD WATER

With hard water, soap solutions form a white precipitate (soap scum) instead of producing lather, because the 2+ ions destroy the surfactant properties of the soap by forming a solid precipitate (the soap scum). A major component of such scum is calcium stearate, which arises from sodium stearate, the main component of soap:

2 C17H35COO- (aq) + Ca2+ (aq) → (C17H35COO)2 Ca (s)

Hardness can thus be defined as the soap-consuming capacity of a water sample, or the capacity of precipitation of soap as a characteristic property of water that prevents the lathering of soap. Synthetic detergents do not form such scums. Hard water also forms deposits that clog plumbing. These deposits, called "scale", are composed mainly of calcium carbonate (CaCO3), magnesium hydroxide (Mg(OH)2), and calcium sulfate (CaSO4) (Hermann, 2006). Calcium and magnesium carbonates tend to be deposited as off-white solids on the inside surfaces of pipes and heat exchangers. This precipitation (formation of an insoluble solid) is principally caused by thermal decomposition of bicarbonate ions but also happens in cases where the carbonate ion is at saturation concentration. The resulting build-up of scale restricts the flow of water in pipes. In boilers, the deposits impair the flow of heat into water, reducing the heating efficiency and allowing the metal boiler components to overheat. In a pressurized system, this overheating can lead to failure of the boiler (Stephen, 2007). The damage caused by calcium carbonate deposits varies on the crystalline form, for example, calcite or aragonite (Coetzee, 1998).

The presence of ions in an electrolyte, in this case, hard water, can also lead to galvanic corrosion, in which one metal will preferentially corrode when in contact with another type of metal, when both are in contact with an electrolyte. The softening of hard water by ion exchange does not increase its corrosivity per se. Similarly, where lead plumbing is in use, softened water does not substantially increase plumbo-solvency (Sorg et al., 1999).

1.3.5  HEALTH CONSIDERATIONS

The World Health Organization says that "there does not appear to be any convincing evidence that water hardness causes adverse health effects in humans" (WHO, 2003). In fact, the United States National Research Council has found that hard water can actually serve as a dietary supplement for calcium and magnesium.  Some studies have shown a weak inverse relationship between water hardness and cardiovascular disease in men, up to a level of 170 mg calcium carbonate per litre of water. The World Health Organization has reviewed the evidence and concluded the data was inadequate to allow for a recommendation for a level of hardness (WHO, 2003). Recommendations have been made for the maximum and minimum levels of calcium (40–80 ppm) and magnesium (20–30 ppm) in drinking water, and a total hardness expressed as the sum of the calcium and magnesium concentrations of 2–4 mmol/L (Frantisek, 2003).

Other studies have shown weak correlations between cardiovascular health and water hardness (Pocock et al., 1981).  Some studies correlate domestic hard water usage with increased eczema in children.  The Softened-Water Eczema Trial (SWET), a multicenter randomized controlled trial of ion-exchange softeners for treating childhood eczema, was undertaken in 2008. However, no meaningful difference in symptom relief was found between children with access to a home water softener and those without.

1.4     THE LIVER

The liver is a vital organ of the digestive system present invertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemical substances necessary for digestion. The liver is necessary for survival; there is currently no way to compensate for the absence of liver function in the long term, although new liver dialysis techniques can be used in the short term. This gland plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, hormone production, and detoxification. It lies below the diaphragm in the abdominal-pelvic region of the abdomen. It produces bile, an alkaline compound which aids in digestion via the emulsification of lipids. The liver's highly specialized tissues regulate a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex molecules, many of which are necessary for normal vital functions (Maton et al., 1993). Estimates regarding the organ's total number of functions vary, but textbooks generally cite it at around 500 or so(Zakim et al., 2002).Terminology related to the liver often starts in hepar- or hepat-from the Greek word for liver, hēpar (ἧπαρ, root hepat-, ἡπατ-).

1.4.1  ANATOMY

The liver is a reddish brown organ with four lobes of unequal size and shape. A human liver normally weighs 1.44–1.66 kg (3.2–3.7 lb), (Cotran et al., 2001) and is a soft, pinkish-brown, triangular organ. It is both the largest internal organ (the skin being the largest organ overall) and the largest gland in the human body. It is located in the right upper quadrant of the abdominal cavity, resting just below the diaphragm. The liver lies to the right of the stomach and overlies the gall bladder. It is connected to two large blood vessels, one called the hepatic artery and one called the portal vein. The hepatic artery carries blood from the aorta, where as the portal vein carries blood containing digested nutrients from the entire gastrointestinal tract and also from the spleen and pancreas. These blood vessels subdivide into capillaries, which then lead to a lobule. Each lobule is made up of millions of hepatic cells which are the basic metabolic cells. Lobules are the functional units of the liver.

1.4.2  CELL TYPES

Two major types of cells populate the liver lobes; parenchymal and non-parenchymal cells. 80% of the liver volume is occupied by parenchymal cells commonly referred to as hepatocytes. Non-parenchymal cells constitute 40% of the total number of liver cells but only 6.5% of its volume. Sinusoidal hepatic endothelial cells, Kupffer cells and hepatic stellate cells are some of the non-parenchymal cells that line the liver sinusoid (Kmie, 2001).

1.4.3  BLOOD FLOW

The liver gets a dual blood supply from the hepatic portal vein and hepatic arteries. Supplying approximately 75% of the liver's blood supply, the hepatic portal vein carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remainder of its blood flow. Oxygen is provided from both sources; approximately half of the liver's oxygen demand is met by the hepatic portal vein, and half is met by the hepatic arteries (Shneider et al., 2008).Blood flows through the liver sinusoids and empties into the central vein of each lobule. The central veins coalesce into hepatic veins, which leave the liver.

1.4.4  PHYSIOLOGY

The various functions of the liver are carried out by the liver cells or hepatocytes. Currently, there is no artificial organ or device capable of emulating all the functions of the liver. Some functions can be emulated by liver dialysis, an experimental treatment for liver failure. The liver is thought to be responsible for up to 500 separate functions, usually in combination with other systems and organs.

SYNTHESIS:

Proteins produced and secreted by the liver a large part of amino acid synthesis. The liver performs several roles in carbohydrate metabolism:

Gluconeogenesis (the synthesis of glucose from certain amino acids, lactate or glycerol)

Glycogenolysis (the breakdown of glycogen into glucose)

Glycogenesis (the formation of glycogen from glucose) (muscle tissues can also do this)

The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. The liver also performs several roles in lipid metabolism: Cholesterol synthesis Lipogenesis, the production of triglycerides (fats).A bulk of the lipoprotein is synthesized in the liver. The liver produces coagulation factors I (fibrinogen), II (prothrombin), V, VII, IX, X and XI, as well as protein C, protein S and antithrombin. In the first trimester fetus, the liver is the main site of red blood cell production. By the 32nd week of gestation, the bone marrow has almost completely taken over that task. The liver produces and excretes bile (a yellowish liquid) required for emulsifying fats and help the absorption of vitamin K from the diet. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder. The liver also produces insulin-like growth factor 1 (IGF-1),a polypeptide protein hormone that plays an important role in childhood growth and continues to have anabolic effects in adults. The liver is a major site of thrombopoietin production. Thrombopoietin is a glycoprotein hormone that regulates the production of platelets by the bone marrow.

BREAKDOWN

The liver breaks down insulin and other hormones. The liver breaks down or modifies toxic substances (e.g, methylation) and most medicinal products in a process called drug metabolism. This sometimes results in toxication, when the metabolite is more toxic than its precursor. Preferably, the toxins are conjugated to avail excretion in bile or urine. The liver converts ammonia to urea (urea cycle).

OTHER FUNCTIONS

The liver stores a multitude of substances, including glucose (in the form of glycogen), vitamin A (1–2 years' supply), vitamin D(1–4 months' supply), vitamin B12 (1–3 years' supply), vitamin K, iron, and copper. The liver is responsible for immunological effects—the mononuclear phagocyte system (MPS) of the liver contains many immunologically active cells, acting as a 'sieve' for antigens carried to it via the portal system. The liver produces albumin, the major osmolar component of blood serum. The liver synthesizes angiotensinogen, a hormone that is responsible for raising the blood pressure when activated by renin, an enzyme that is released when the kidney senses low. The liver also functions as a blood reservoir, being an expandable organ. Large quantities of blood can be stored in its blood vessels, its normal blood volume in the hepatic veins and that in the hepatic sinuses is about 450ml. During cardiac failure with peripheral congestion, the liver expands, and 0.5 to 1 liter of extra blood is occasionally stored in the hepatic veins and sinuses, due to high pressure in right atrium which causes back pressure in the liver.

1.4.5  DISEASES OF THE LIVER

The liver supports almost every organ in the body and is vital for survival. Because of its strategic location and multidimensional functions, the liver is also prone to many diseases (NDDIC, 2010).The most common include: Infections such as hepatitis A, B,C, D, E, alcohol damage, fatty liver, cirrhosis, cancer , drug damage (particularly by acetaminophen (paracetamol) and cancer drugs).Many diseases of the liver are accompanied by jaundice caused by increased levels of bilirubin in the system. The bilirubin results from the breakup of the hemoglobin of dead red blood cells;normally, the liver removes bilirubin from the blood and excretes it through bile. There are also many pediatric liver diseases including biliary atresia, alpha-1 antitrypsin deficiency, alagille syndrome, progressive familial intra hepatic cholestasis, and Langerhans cell histiocytosis, to name but a few. Diseases that interfere with liver function will lead to derangement of these processes. However, the liver has a great capacity to regenerate and has a large reserve capacity. In most cases, the liver only produces symptoms after extensive damage. Liver diseases may be diagnosed by liver function tests, for example, by production of acute phase proteins.

1.4.6  LIVER FUNCTION TESTS

Liver function tests (LFTs or LFs) are groups of blood tests that give information about the state of a patient's liver (Lee, 2009). These tests include prothrombin time (PT/INR), aPTT, albumin, bilirubin (direct and indirect), and others. Liver transaminases (AST or SGOT and ALT or SGPT) are useful biomarkers of liver injury in a patient with some degree of intact liver function (Johnston, 1999). Most liver diseases cause only mild symptoms initially, but these diseases must be detected early. Hepatic (liver) involvement in some diseases can be of crucial importance. This testing is performed on a patient's blood sample. Some tests are associated with functionality (e.g., albumin), some with cellular integrity (e.g., transaminase), and some with conditions linked to the biliary tract (gamma-glutamyl transferase and alkaline phosphatase). Several biochemical tests are useful in the evaluation and management of patients with hepatic dysfunction. These tests can be used to detect the presence of liver disease, distinguish among different types of liver disorders, gauge the extent of known liver damage, and follow the response to treatment. Some or all of these measurements are also carried out (usually about twice a year for routine cases) on those individuals taking certain medications, such as anticonvulsants, to ensure the medications are not damaging the person's liver.

ALBUMIN

Albumin is a protein made specifically by the liver, and can be measured cheaply and easily. It is the main constituent of total protein (the remaining from globulins). Albumin levels are decreased in chronic liver disease, such as cirrhosis. It is also decreased in nephrotic syndrome, where it is lost through the urine. The consequence of low albumin can be edema since the intravascular oncotic pressure becomes lower than the extravascular space. An alternative to albumin measurement is prealbumin, which is better at detecting acute changes (half-life of albumin and prealbumin is about 2 weeks and about 2 days, respectively).

TOTAL BILIRUBIN

Measurement of total bilirubin includes both unconjugated and conjugated bilirubin. Unconjugated bilirubin is a breakdown product of heme (a part of hemoglobin in red blood cells). It is very hydrophobic and is mainly transported bound to albumin circulating in the blood. Addition of high-concentration hydrophobic drugs (certain antibiotics, diuretics) and high free fatty acids can cause elevated unconjugated bilirubin. Heme can also come from myoglobin, found mostly in muscle, cytochromes, found mostly in mitochondria, catalase, peroxidase, and nitric oxide synthase. The liver is responsible for clearing the blood of unconjugated bilirubin, and about 30% of it is taken up by a normal liver on each pass of the blood through the liver by the following mechanism: bilirubin is taken up into hepatocytes, 'conjugated' (modified to make it water-soluble) by UDP-glucuronyl-transferase, and secreted into the bile by CMOAT (MRP2), which is excreted into the intestine. In the intestine, conjugated bilirubin may be metabolized by colonic bacteria, eliminated, or reabsorbed. Metabolism of bilirubin into urobilinogen followed by reabsorption of urobilinogen accounts for the yellow color of urine, as urine contains a downstream product of urobilinogen. Further metabolism of urobilinogen into stercobilin while in the bowels accounts for the brown color of stool. Thus, having white or clay-colored stool is an indicatorfor a blockage in bilirubin processing and thus potential liverdysfunction or cholestasis.Increased total bilirubin (TBIL) causes jaundice, and canindicate a number of problems

DIRECT BILIRUBIN

The diagnosis is narrowed down further by evaluating the levels of direct bilirubin. If direct (conjugated) bilirubin is normal, then the problem is an excess of unconjugated bilirubin (indirect bilirubin), and the location of the problem is upstream of bilirubin conjugation in the liver. Hemolysis, or internal hemorrhage can be suspected. If direct bilirubin is elevated, then the liver is conjugating bilirubin normally, but is not able to excrete it. Bile duct obstruction by gallstones, hepatitis, cirrhosis or cancer should be suspected.

SERUM TOTAL PROTEIN

Serum total protein, also known as total protein, is a biochemical test for measuring the total amount of protein in serum. Protein in the plasma is made up of albumin and globulin. The globulin in turn is made up of α1, α2, β, and γ globulins. These fractions can be quantitated using protein electrophoresis, but the total protein test is a faster and cheaper test that estimates the total of all fractions together. The traditional method form easuring total protein uses the biuret reagent, but other chemical methods such as Kjeldahl method, dye-binding and refractometry are now available. The measurement is usually performed on automated analysers along with other laboratory tests.

ALKALINE PHOSPHATASE

Alkaline phosphatases are a family of zinc metaloenzymes, with a serine at the active center. Alkaline phosphatase from the liver, bone and kidney are derived from same gene but that of the intestine and placenta are derived from different gene (Rosalki and Mcintyre, 1999). The test should not be done on plasma if cirate, oxalate or EDTA were used as anticoagulants, they form a complex with zinc and the alkaline phosphatase, causing irreversible enzyme inactivation ( Rosalki and Mcintyre, 1999).

AMINOTRANSFERASES

Aminotransferases are the most commonly used and specific indicators of hepatocellular necrosis. These enzymes include aspartate aminotransferase (AST) and alanine anminotransferase (ALT). ALT is localized to the liver but the AST is present in a wide variety of tissues like heart, skeletal muscle, kidney, brain and liver. ( Friedman et al., 2003; Rosen and Reefe, 2000). Whereas AST is present in the both the mitochondria and cytosol of hepatocyes, ALT is located at the cytosol (Rosen and Keefe, 2000; Sherlock, 1997).

 

 

 

 

 

 

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