Biochemistry 2 for Dental Students

62BCH 2

Biochemistry BCH 262

This course Prepared by

Dr.Eman Saqr

2

Course Directors

***********

Associate Prof. Dr. Ehab(Male) Assistant Prof.Dr. Eman Saqr (Female)

Recommended Books, References & Teaching

Materials

•Textbook of biochemistry for dental students by

DM Vasudevan, Sreekumari S and Kannan

Vaidyanathan, 2nd Edition 2011.

•Biochemistry by P.C. Champe, R.A. Harvey and D.R.

Ferrier 3rd Edition 2005 Lippincott’s Illustrated

Reviews

•Handbook of biochemistry (For allied and nursing

students) by Shivananda Nayak B 1st Edition 2007.

Teaching Methodology: • Lecture. 1hours •Practical Session. 2 hours Assessment Tools for each semester: 20% - Mid-Exam 40% - Final Exam 20% - Assignments 20% - Practical

Assignments are: • 5 marks for each of Research project, Oral, and Quizzes.

• 5 marks for attendance, attitude and participation during lecture session.

Lectures schedule-Male-Female Week Date/Saturday Subject Reading assignment Quizzes

1

26/1/2013

Registration

2 2/2/2013

Introduction of

biochemistry and

explain the course

syllabus

Plasma protein

Text book of

Biochemistry for

Dental Students 2th

edition

Chapter 13pp. 122-127

3 9/2/2013

Heme and haemoglobin

metabolism (part 1)

Chapter 15 pp. 137-142

4 16/2/2013 Heme and haemoglobin

metabolism (part 2)

Chapter 15 pp. 142-148 Quiz 1 in the time of

practical session

5 23/2/2013

Connective tissues Chapter 22 pp. 198-201

6 2/3/2013

Fat soluble vitamins Chapter 16 pp. 149-155 Quiz 2 in the time of

practical session

7 9/3/2013

Mid Term Exam

All questions are short notes

8 16/3/2013

Fat soluble vitamins

(continue)

Chapter 16 pp. 149-

155

9

23/3/2013

Mid Term Vacation

10 30/3/2013 Water soluble vitamins Chapter 17 pp. 156-

165

11 6/4/2013 Minerals Chapter 18 pp. 167-

176

12 13/4/2013

Biological buffers Chapter 21 pp. 190-

196

Quiz 3 in the time of

practical session

13 20/4/2013

Biochemistry of teeth,

saliva and dental caries

(part 1)

Chapter 8 pp. 67-75

14 27/4/2013

Biochemistry of teeth,

saliva and dental caries

(part 2)

Chapter 8 pp. 67-75 Quiz 4 in the time of

practical session

15 6/5/2013

Control and integration

of metabolism

Chapter 31 pp. 253-

264

16 13/5/2013

Practical Exam

17 20/5/2013

Oral Exam

18 27/5/2013

Final Exam

19 1/6/2013

5/6/2013 Summer Vacation

Research Project • Each one can choose one from the following hormone as

a subject of the project:

• ACTH, ADH, FSH, LH, TSH, PTH, Glucagon, Calcitonin, GnRH, TRH, ANF, Estrogens, Progesterone, Androgens, Catechol amines, Insulin, Glucocorticoids, Acetyl choline.

• Dead line to record names of each one with his/her subject on Wednesday, 13/2/2013.

• Five students from each group will discuss their project weekly starting from the third week according to their presence in the attendance sheet.

• The only excuse is by recommended medical certificate.

For Female Time Table Group One Group Two Group Three

Theoretical

Wednesday Wednesday

Wednesday

11-12 12-1 1-2

Class 12 Class 12 Class 12

Practical

Monday Monday Monday

12-2 8-10 10-12

Office Hours Saturday 12-2

For Male Time Table Group One Group Two Group Three

Theoretical

Wednesday Wednesday Wednesday

5-6 5-6 5-6

Audio-3 Audio-3 Audio-3

Practical

Monday Monday Monday

8-10 4-6 6-8

Office Hours Saturday 6-8

Blood Biochemistry

Plasma proteins,

Immunoglobulin and

Hemoglobin

Blood • Total blood volume is about 4.5 to 5 liters in adult human being.

• Blood is a highly specialized tissue composed of more than 4,000

different kinds of components. Four of the most important ones are

red cells, white cells, platelets, and plasma.

• Normally, 55% of our blood's volume is made up of plasma.

• Plasma also contains blood clotting factors, sugars, lipids, vitamins,

minerals, hormones, enzymes, antibodies, and other proteins.

• It is likely that plasma contains some of every protein produced by

the body--approximately 500 have been identified in human plasma

so far.

• The de-fibrinated plasma is called serum, which lacks coagulation

factors including prothrombin and fibrinogen.

Plasma Proteins • Total protein content of normal plasma is 6 to 8

g/100 ml.

• The plasma proteins consist of:

Albumin (3.5 - 5 g/dl).

Globulins (2.5 – 3.5 g/dl).

Fibrinogen (200 – 400 mg/dl).

• The albumin : globulin ratio is usually between 1.2 : 1 to 1.5 : 1.

• Almost all plasma proteins, except immunoglobulin are synthesized in liver.

Electrophoresis

• In clinical laboratory, electrophoresis is employed regularly for separation of serum proteins.

• The term electrophoresis refers to the movement of charged particles through an electrolyte when subjected to an electric field

Normal value and Interpretations

• In agar gel electrophoresis, normal serum is separated into five bands,

Albumin, Alpha-1-globulin, Alpha-2-globulin, Beta-globulin and Gamma globulin.

Albumin has the maximum and gamma globulin has the minimum mobility in the electrical field.

Abnormal Patterns in Clinical Diseases

• Various abnormalities can identified in the electrophoretic pattern.

Chronic infections:

The gamma globulins are increased, but the increase is smooth and wide based.

Transport proteins

Blood is a watery medium; so lipids and lipid soluble substances will not easily mix in the blood. Hence, such molecules are carried by specific carrier proteins.

1. Albumin: It is an important transport protein, which carries bilirubin, free fatty acids, calcium and drug.

2. Pre-albumin or transthyretin: It carries thyroid hormones, thyroxin (T4) and tri-iodo thyronine (T3). Its half life in plasma is only 1 day.

3. Thyroxine binding globulin (TBG): It is the specific carrier molecule for thyroxine and tri-iodo thyronine. TBG level is increased in pregnancy; but decreased in nephrotic syndrome.

4. Retinol binding protein (RBP): It carries vitamin A.

5- Transcortin or cortisol binding globulin (CBG): Transports cortisol and corticosterone.

6. Transferrin: It carries iron in plasma.

Acute Phase Proteins

• The level of certain proteins in blood may increase 50 to 1000 folds in various inflammatory and neoplastic conditions.

• Such proteins are acute phase proteins.

• Important acute phase proteins are:

1. C-Reactive Protein (CRP).

2. Ceruloplasmin.

1. C-Reactive Protein (CRP):

• It is thus named because it reacts with C-polysaccharide of capsule of pneumococci.

• It is synthesized in liver. • It can stimulate macrophage

phagocytosis. • When the inflammation has subsided,

CRP quickly falls, followed later by ESR (erythrocyte sedimentation rate).

2. Ceruloplasmin: I. Ceruloplasmin is blue in colour.

II. It is synthesized in liver. It contains 6 to 8 copper atoms per molecule.

III. Ceruloplasmin is also called Ferroxidase, an enzyme which helps in the incorporation of iron into transferrin.

IV. Ceruloplasmin is an acute phase protein. So its level in blood may be increased in all inflammatory conditions, collagen disorders and in malignancies.

Albumin

Function of Albumin 1. Colloid osmotic pressure of plasma • Protein cannot easily escape out of blood vessels,

and therefore, proteins exert the ‘effective osmotic pressure’ (EOP).

• The maintenance of blood volume is dependent on EOP.

• If protein concentration reduced, so EOP will reduced, then return of water into blood vessel is diminished. Leading to accumulation of water in tissues, this called edema.

2. Transport Function Albumin is the carrier of various hydrophobic

substances in the blood. Being a watery medium, blood cannot solubilize lipid components and lipophilic compounds such as:

I. Bilirubin and nonesterified fatty acids are specifically transported by albumin.

II. Drugs (sulpha, aspirin, salicylates, dicoumarol, phenytoin).

III. Hormones: Steroid hormones, thyroxine.

IV. Metals: Calcium, copper and heavy metals are nonspecifically carried by albumin.

3. Nutritional function

• All tissue cells can take up albumin by pinocytosis.

• It is then broken down to amino acid level.

• So albumin may be considered as the transport form of essential amino acids from liver to other tissues.

Edema Hypoalbuminemia will result in tissue edema.

I. Malnutrition, where albumin synthesis is depressed (generalized edema).

II. Nephrotic syndrome, where albumin is lost through urine (facial edema). Presence of albumin in urine is called albuminuria.

III. Cirrhosis of liver (mainly ascites). Albumin synthesis is decreased.

IV. Chronic congestive cardiac failure, venous congestion will cause increased hydrostatic pressure and decreased return of water into capillaries and so pitting edema of feet may result.

Albumin-Globulin Ratio

• In hypoalbuminemia, there will be a compensatory increase in globulins which are synthesized by the reticuloendothelial system.

• Albumin-globulin ratio (A/G ratio) is thus altered or even reversed. This again leads to edema.

Immunoglobulins

• Immunoglobulin is abbreviated as Ig.

• The terms gamma globulin and immunoglobulin are not synonymous.

• Gamma globulin is the term describing its mobility in electrical field.

• Most of the immunoglobulins have the gamma mobility; but some may move along with beta or even with alpha globulins.

• Immunoglbulin is a functional term, while gamma globulin is a physical term.

Heavy and light chains • Immunoglobulin consists of light chain (less number

of amino acid) and heavy chain (large number of amino acid).

• According to heavy chain immunoglobulin differentiated to 5 major classes:

1. IgG is made up of heavy chain ɣ (gamma).

2. IgM has μ (mu) heavy chain.

3. IgA has α (alpha) heavy chain.

4. IgD contains δ (delta) chain.

5. IgE heavy chain called ε (epsilon).

• The light chain either ҡ (kappa) or λ (lambda).

Different classes of Immunoglobulins 1. Immunoglobulin G (IgG)

• IgG contains 2 heavy chains(composed of 440 amino acids) and 2 light chains (composed of 214 amino acids) combined through disulphide bridges.

• It is the antibody seen in secondary immune response.

• It can pass from vascular compartment to interstitial space.

• It can cross placental barrier, and protects the new born child from infections.

2. Immunoglobulin M (IgM)

• Ig M are macroglobulins.

• Five subunits, each having 4 peptide chains (total 10 heavy chains and 10 light chains) are joined together by a J-chain polypeptide.

• It can combined with 5 antigen simultaneously, and so IgM is very effective for agglutinating bacteria.

• Being a large molecule, it cannot come out of vascular space.

• IgM are the predominant class of antibodies in primary response.

Immunoglobulin M (IgM)

3. Immunoglobulin A (IgA)

• IgA usually are dimers (total 4 heavy chains and 4 light chains). The J-chain connects the dimers.

• They are secretory antibodies seen in seromucous secretions of gastrointestinal tract, nasopharyngeal tract, urogenital tract, tears, saliva, sweats, etc.

• The dimers are stabilized against proteolytic enzymes by the secretory piece.

4. Immunoglobulin E (IgE) • They mediate allergy, hypersensitivity and anaphylaxis. • They have the property to fix on mast cells and

basophils. When certain antigens such as penicillin are injected a few times, IgE class antibodies are produced which anchor on mast cells.

• When the same antigen is injected next time, the antigen fixes on cell surface antibodies, causing mast cell degranulation, and release of histamine and slow reacting substance.

• This leads to vasodilatation, hypotension and bronchiolar constriction.

• This is the basis of penicillin anaphylaxis, hay fever caused by fungus, asthma by pollen and urticaria by absorbed food elements.