I- URINE

1. I- URINE Physical properties of urine: 1-Color of urine:Normal urine ordinary possesses an amber yellow The color of normal urine is due to a pigment called –urochrome (oxidative product of colourless urochromogen- urobilin , riboflavin, uroerythrine 2-Urine appearance:Normal urine is ordinarily clear and transparent when voided. Causes of turbidity: 1-Alkaline urine due to precipitation of calcium and magnesium pfosphate. 2- On standing for a time, (cloudy) consisting principally of nucleoprotein or mucoid and epithelial cells forms.(give ammonical fermentation giving alkaline urine) . 3- Haematuria , pyuria (pus in urine ) , bacteruria, chyluria and crystaluria

2. 3-Odor of urine: Normal urine has a faint aromatic odor. • Acetone odour :in cases of ketosis • Offensive odour : in cases of pyuria • Odour of burned sugar : Maple syrup urine 4-Specific gravity of urine (Sp.G.): Normal urine exhibits Sp.G. between 1.015 and 1.025 5-Reactions: Normal mixed urine for 24 hours is generally acidic (pH 5.0 – 6.5),

3. 6-Volume:Large volume of urine is called polyuria and decreased volume of urine is called oliguria.Factors affecting urine volume are: a) Dietetic factors: • High protein diet causes an increase in the amount of urine. • The volume of urine depends also on water intake either in the form of water or watery foodstuffs as milk,juices, water mellon, etc… • The volume of urine depends also on the amount of salts in diet. b) Physiological factors: • Volume of urine is decreased in summer and increased in winter due to the activity of sweat glands in summer. • The volume of urine is decreased after excessive muscular exercises due to much sweating. • Less urine is passed during the night (1/2 litre) than during the day (1 litre).

4. c) Pathological factors: • Diabetes mellitus: Increased volume of urine due to hyperosmosis by glucose resisting reabsorption from the kidney tubules. • Diabetes insipidus: The volume of urine may reach 4-6 litres or even much more. • Hypertension: The volume of urine is increased due to increased glomerular filtration. • Some diseases of the nervous system. d) Diuretic drugs: • The volume of urine is increased due to increased glomerular filtration. Drugs such as salicylates, acetates and calomel increase the volume of urine excreted.

5. Oliguria occurs in the following cases: • Inflammatory kidney diseases. • Heart failure • Oedema. • Fevers. • Profuse haemorrhage. • Vomitting. • Obstruction in urine passages. • Excessive sweating.

6. Normal constituents of urine The quantitative composition of the urine reflects the function of the kidneys in preserving important aspects of homeostasis and of the normal equilibrium between the organism and its environment. Urine contains organic and inorganic constituents: A- Organic constituents of urine: 1-Non-protein nitrogenous constituents (NPN). 2-Non-nitrogenous organic constituents. • Non-protein nitrogenous constituents (NPN): - These are substances not precipitated by the usual protein precipitating agents. These are usually the end products of protein metabolism in the body

7. The main NPN constituents of urine are: a) Urea: • - It is the main solid of urine. It is about 20 - 40 gm/day or 1/3 of the total proteins taken/day. All the urea in urine is of exogenous origin. If urine is left for a long time exposed to atmosphere, urea is acted upon by bacteria and ammonia is liberated giving ammoniacal odor to urine. b) Uric acid: • - It is the end product of catabolism of purines in man. Its amount in urine is about 0.7 gm/day. Half of it is of exogenous origin produced from nucleoproteins taken in diet, while the other half is of endogenous origin produced from catabolism of nucleoproteins in the body. It is one of the normal reducing substances in urine. c) Ammonia: • - It is about 0.7 gm/day. 60% of it is derived from the glutaminase reaction,

8. d) Creatinine: • - It is about 1-1.8 gm/day in males and 0.7-1 gm/day in females. This difference is due to the muscle bulk of males. Creatinine excreted on creatinine free diet is constant regardless of urine volume and is known as creatinine coefficient. It is totally of endogenous origin. It is one of the normal reducing substances present in urine. e) Creatine: • - It occurs in very small amounts in the urine of adults. It appears in urine in the following conditions: • In children • Periodically in females. • After labour and during the last days of pregnancy. f) Amino acids: - Amino acids are present in urine in small amounts either in the free state or in combined state, e.g., hippuric acid contains glycine, mercapturic acid containing cysteine, etc.

9. 2-Non-nitrogenous organic constituents: - These non-nitrogenous organic constituents include: • Carbohydrates: • - Small undetected amount of glucose, pentoses after intake of high amount of fruits, fructose and galactose rarely appear in urine. • Lipids: - Very small amount of short chain fatty acids. • Organic acids: • The main organic acids appearing in urine include glucuronic acid which appears in urine in conjugation with other substances, e.g., with sex hormones, etc. Citric acid, lactic acid and oxalic acid are other examples of organic acids appearing in urine. • B- Inorganic Constituents of Urine: • - These include chlorides, phosphates, carbonates and sulfates. 1-Chlorides: • - The source of chlorides present in urine is the diet. Its amount varies from 10-15 g/day. Chlorides and urea are the main substances affecting the specific gravity of the urine. The

10. chloride content is diminished in the following cases: • During fasting or starvation. • In poor chloride intake. • In case of prostatic obstruction. • In pneumonia as the chlorides are retained in exudates. • In case of severe vomitting. • In case of severe diarrhoea. • In case of severe burns. • In certain kidney diseases associated with chloride retention. • In cases of nephrosis, nephritis, cardiac failiure and adrenal cortical hyperfunction. • In adrenal cortical insufficiency and in Addison’s disease

11. 2-Sulphates in urine: • - The presence of sulphates in urine is principally due to the oxidation of sulphur present in the sulphur amino acids which are cystine, cysteine and methionine. The amount of sulphates in urine depends mostly on diet. Sulphates are present in three forms: • Inorganic sulphates of Na+, K+ and Mg+. These form 90% of the total amount of sulphates present. • Etherial sulphates, e.g., indican: Etherial sulphates consist of sulphate esters of phenols (as indoxyl, skatoxyl), cresols and other similar hydroxyl organic compounds. • Neutral sulphur: Includes the unoxidised or the uncompletely oxidised forms of sulphur. It includes cystine, cysteine, methionine, methyl and ethyl mercaptan, urochromes, thiosulphates, etc…. Neutral sulphur excreted daily in normal urine is about 0.08 – 2 gm. This fraction of sulphur is increased in the case known as cystinuria. Cystinuria is a rare inborn error of metabolism associated with much excretion of cystine in urine. The amount of cystine excreted may be 25 times that excreted by normal individual

12. 3-Phosphates: • - Phosphates in urine are derived from the oxidation of phosphoproteins of diet (as casein of milk and vetillin of egg yolk) phospholipids and nucleoproteins. Phosphates of urine (1 - 2 g/day) may be divided into: • Alkali phosphates (Na+ and K+) 65%. • Earthy phosphates (Ca2+ and Mg+) 35%. • - Urine contains two forms of phosphates acidic (monobasic) and basic phosphates (dibasic). The pH of urine generally depends on the ratio between acidic and basic phosphates. Phosphate amount excretion in urine depends upon: • Phosphate content of the diet. • The need of the body to phosphates as in case of bone formation or during lactation. • Ca2+ and Phosphorus metabolism. • - Phosphates are decreased in the following cases: • During pregnancy. • During lactation. • During treatment of rickets by vitamin D. • During healing of major fractures. • During administration of Ca2+. • In case of hypoparathyroidism, nephritis and some infectious diseases.

13. Phosphates are increased in the following cases: • In case of rickets in children. • In case of osteomalacia in adults. • In case of hyperparathyroidism. 4-Glucuronates: Glucuronic acid during the process of detoxication in liver, combines with some toxic substances such as phenols, benzoic acid … etc. to give rise to the corresponding glucuronates. Glucuronates reduce Fehling solution but do not give positive alcoholic fermentation test. 5-Vitamins: All water soluble vitamins are excreted in urine. The fat soluble vitamins are not excreted by urine but are excreted in faeces. 6-Oxalic acid: Oxalic acid is a normal constituent of urine (10 - 50 mg/day). It is mainly derived from the endogenous metabolism of carbohydrates, proteins and oxalates derived from certain foodstuffs. An abnormal increase in oxalic acid excretion is known as oxaluria. This occurs in diabetes mellitus and certain liver and nervous diseases. 7-Citric acid: About 0.2 - 1.2 gm. citric acid is excreted daily. It is formed continuously in carbohydrate metabolism through Krebs' cycle. 8-Lactic acid: About 50 - 200 mg. Lactic acid are excreted daily. Its content in urine is increased in severe muscular exercises.

14. Abnormal constituents of urine: 1-Proteins especially albumin (albuminuria). 2-Sugar (see glucosuria in carbohydrate metabolism). 3-Ketone bodies (see ketonuria in lipid metabolism). 4-Bile salts and bile pigments (see jaundice in prophyrine metabolism). 5-Blood (hematuria) mainly in Bilharziasis, stones in urinary tract and inflammation of kidney. 6-Indican (see metabolism of tryptophan). 7-Porphobilinogen in porphyrias.

15. II- MILK • Milk is the secretion of the mammary glands in humans and animals. It is a nearly complete diet. Physical Characters: • Color: White: Due to presence of fat globules and calcium phosphate. Yellowish: Due to presence of carotenoids (e.g. Cow’s Milk and colostrum). • Reaction: pH: 6.6 - 7.4 for Human’s milk, and for 7.7 Cow’s milk. It is an excellent buffer as it contains protein, phosphate, bicarbonate and citrate. • Specific gravity: 1025 - 1035 at 32 oC for Human’s milk. 1020 - 1032 at 32 oC for Cow’s milk. When milk is skimmed (deprived of fat), its specific gravity rises (due to removal of light constituent). When water is added, specific gravity decreases.

16. Composition of Milk: • Proteins: • - It is 1.2 gm/dL Milk. It is slightly lower in human than animal milk. It is formed of Casein, lactalbumin, lactglobulin and enzymes. • a) Casein: (25%): It is phosphor protein of high biological value. It combines with calcium ion to form insoluble calcium caseinate (milk clot). It prevents rapid passage of milk from the stomach to the intestines so gives the sense of fullness. Casein/lactalbumin + lactglobulin ratio is 1:3, and therefore, easily digested. Casein is rich in methionine, but poor in cysteine and cystine, so it is not coagulated by heat, gives negative sulfur test and precipitated at pH 4.6. • b) Lactalbumin and Lactglobulin (75%): They are soluble compounds, so easily digested. They also contain -globulin that gives the body immunoglobulins. • c) Enzymes:Protease, lipase, amylase, peroxidase, catalase, alkaline phosphatase, and aldehyde oxidase (Schardinger's enzyme). Detection of the last enzyme indicates that milk was not boiled. Milk + Methyl blue + formaldehyde  Blue indicates boiled milk, whereas, colorless indicates fresh non-boiled. If milk is not boiled, Schardinger’s enzyme is present, so it oxidizes formaldehyde and use methyl blue as hydrogen carrier, the later became colorless when reduced. If milk is boiled, Schardinger’s enzyme is destroyed, so no reaction occurs, i.e., remains blue (color of methyl blue).

17. -d-Lactose, is 7 g/dL milk. Lactose is the milk sugar; it is less sweaty than sucrose so, this allows the baby to take a large amount of milk without nausea. Lactose is a non-fermentable sugar, so it does not produce CO2 in the stomach and consequently the baby does not suffer from abdominal colic. • - In intestines lactose is hydrolyzed to glucose (fermentable) and galactose (non-fermentable). Most of the glucose as well as galactose are absorbed by intestinal mucosa. However, some of glucose will undergo fermentation, which gives CO2 that helps the peristaltic movements for defection. • - Lactose helps the growth of lactic acid producing bacteria in the intestines so it helps calcium, phosphorus, iron and copper absorption. It also inhibits the growth of putrefactive bacteria. C-Fat: • - The human and animal milk fats are the same, (3.5 g/dL milk). Milk fat is mainly triglycerides containing saturated fatty acids (48%) and unsaturated (essential) fatty acids (52%). Milk contains little cholesterol and phospholipids. E-Minerals: • - Milk is rich in Ca2+, P-, K+ and Cl-. It contains fair amount of Na and Mg and poor in Fe and Cu2+. Generally, minerals are low in human milk. Milk does not cope well with the body needs of iron. Calcium and phosphorus are present in the optimum ratio for absorption (2:1). F-Vitamins: • - Milk is rich in vitamin A and B2, but poor in vitamin C, D, and K.

18. Differences between cow and human milk: • - Cow milk is commonly used to make artificial milks given as a substitute for human milk in the nutrition of young infants. The main differences between human and cow milks are shown in the table below:

20. Colostrum It is a yellowish fluid secreted by the mammary gland during the 1st week of lactation. It differs from ordinary (late) milk in that: • It is yellow in color due to the presence of excess carotenoids. • It contains more proteins, minerals, and is especially rich in globulins (giving immunity against diseases). • It contains fewer fats and fewer carbohydrates. - Functions of colostrum: • It contains anti-bodies. • It has a laxative effect. • It is easily digestible (less fat).