Essential And Trace Ions PDF

Lec.2 Essential and Trace Ions By Dr.Alyaa Sami  Essential and Trace Ions Naturally occurring, inorganic substances required in humans and are necessary for their growth, development and health. Essential trace elements Iron Zinc Copper Iodine Iron Iron is the most e...

Lec.2 Essential and Trace Ions By Dr.Alyaa Sami  Essential and Trace Ions Naturally occurring, inorganic substances required in humans and are necessary for their growth, development and health. Essential trace elements Iron Zinc Copper Iodine Iron Iron is the most essential trace element it present wherever respiration occure so it essential in: The elementary metabolic process in the cell In the respiration chain, iron function as an electron carrier for the transport of molecular oxygen Both functions depends on the ability of iron to exist in different states of oxidation and bonding Most of iron found in the body in association with two types of protein: 1- Hemoprotein (HEME iron protein) 2- Iron storage and transport proteins Hemoprotein (HEME iron protein) It responsible for respiration and for carrying oxygen eg. Cytochrome C ▪ is a small hemoprotein found in the mitochondrion. Its a respiratory enzyme in which iron is complexed to porphyrin (heme) ring which in turn covalently bonded to protein portion of the atom. ▪ The iron function as electron carrier and can be present as ferric (Fe+3) orferrous (Fe+2) as its picks up or donate electrons. Fe2+ (reduced) Fe3+ (oxidized)  Hemoglobin (Hb) consist of 4 proteins chains each of which contains a heme unit (ferrous iron + porphyrin ring).The iron complexes molecular oxygen by utilizing vacant orbitals which can be used by pair of nonbonding electrons from oxygen.  Myoglobin iron and O2 binding protein in muscle Iron storage and transport proteins 1- Ferritin and hemosiderin They are iron storage proteins found in liver, spleen and bone marrow. Ferritin: Water soluble iron protein, it stores iron in ferric form(Fe+3) and release it in the ferrous form (Fe+2). Hemosiderin water insoluble, dehydrated ferritin. 2-Transferrin is the major iron transport protein. It’s a glycoprotein, one molecule of transferrin can carry two iron ions in form of Fe3+. Iron Iron absorbed in ferrous form which is measurable in blood as free ion Body requirements 0.5-2 mg/day Preparations of iron Oral Ferrous sulfate 20% iron Ferrous fumarate 32.8% iron (less irritating than Ferrous sulfate and resist oxidation upon exposure to air) Ferrous gluconate 11.6% iron Parenteral Iron dextran injection (100mg) iron Iron deficiency When iron is deficient, Hb cannot be produced so unable to deliver sufficient oxygen to the tissues, this is known as iron deficiency anemia (30% of anemic population are due to iron deficiency) Symptoms Asymptomatic Weakness, headache, irritability, and fatigue Treatment 3-6mg of elemental iron / kg / day Zinc Second most abundant trace element. Zinc (Zn) is a bluish white, lustrous metal. Zinc and it’s compounds are used in skin lotions, in the treatment of Wilson’s disease and in many medications. It is component of metalloenzymes (carbonic anhydrase, lactate dehydrogenase, glutamate dehydrogenase and alkaline phosphatase) Zinc is responsible for the regulation of: Growth and development Immune system Collagen synthesis Wound healing Bone metabolism Taste, smell & vision Reduce the time period of diarrhea Zinc Body content 2.5 g 60% in muscle, 30% in bone, 10% in body tissues and organs Daily requirement: 8 – 11 mg / day Zinc deficiency Deficiency of Zn has serious consequence : 1- Failure metabolism of nucleic acids (cell division, growth and differentiation) 2- Multisystemic dysfunction as growth retardation, hypogonadism, ophthalmologic, gastrointestinal, neuropsychiatric symptoms. Zinc deficiency Symptoms: in children (growth retardation & skeletal abnormalities) in adults ( smell & taste, appetite, skin lesions and hair loss) Treatment: zinc supplements 45-100 mg/day Zinc preparations: Zn sulphate (oral) Topical (10%) zinc Copper Copper (Cu) is widely distributed in nature, it is the 3 rd most important trace element. Daily requirement 2-5 mg / day The amount of copper absorbed from the intestine is 50%-80% of ingested copper. Copper is solubilized in stomach acid and absorbed from the stomach and upper small intestine. From the intestine, copper moves into the blood where it exists first as copper albumin complex, then goes to the liver where the copper become part of copper protein, ceruloplasmin. Copper is found in the brain in form of cerebrocuprein, and in blood cells as erythrocuprein. Copper Three roles for copper to prevent anemic conditions: 1- facilitate iron absorption. 2- Stimulates enzymes involve heme and/or globin biosynthesis. 3- Could be involve in the metabolism of stored iron. Copper Other roles of copper: 1- It is important in oxidative phosphorylation (ATP production). 2- It is associated with the formation of aortic elastin. 3- It is a component of tyrosinase , an enzyme responsible for conversion of tyrosine to the black pigment, melanin. 4- It is an essential cofactor for number of enzymes: (superoxide dismutase, cytochrome oxidase (COX), tyrosinase and monoamine oxidase (MAO)) Deficiency of Copper Observed in premature infants Deficiency is related to malnutrition, malabsorption, chronic diarrhia and prolong feeding with low-copper diet. Copper depletion increase risk of coronary heart disease Wilson disease: Is a condition of excess copper storage. It is of genetic origin. There is a decrease in ceruloplasmin concentration in the blood ,and characterized by presence of large amounts of copper in the brain along with an excessive urinary output ,increased copper levels in liver, brain, kidney, and cornea. Pencillamine is the drug of choice which is a chelating agent , in addition to diet restriction. Iodine (Iodide) Iodine (as iodide) is one of the essential trace element, it is purple – black solid, sublimes into purple gas. The daily requirements of iodine is 140 mcg in male 100 mcg in female Importance of Iodine Iodine is absorbed in the form of iodide. Completely absorbed from stomach and upper intestine then it is stored in the thyroid where it is used for the synthesis of T3 and T4. Iodine is an essential ion necessary for synthesis of thyroid hormone which play important role in the metabolic process these hormones include: Thyroxine (T4) – 4 atoms of iodine per molecule. Triiodothyronine (T3) – 3 atoms of iodine per molecule. Iodine After absorption of iodide, it’s uptake is governed by many factors: 1- condition of local thyroid tissue if it is tumorous then uptake is slower than normal tissue 2- the concentration of inorganic iodide in the blood high levels of iodine in blood lead that only small part of administered iodide is utilized. 3- the anterior pituitary hormone thyrotropin level in blood Directly related in utilization of iodine in the formation of thyroid hormones & control the release of thyroid hormones from thyroid gland Iodine preparation Strong iodine solution (Lugol’s Solution) contains 5 g of iodine and 10 g of potassium iodide / 100 ml Sources of the essential trace elements Iron : whole grain, beans, liver Zinc : red meat, fish, beans, dark chocolate Copper : red meat, sea food, nuts Iodine : iodized salt