Sciencegajab

 VACCINATION       • In vaccination, a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) are introduced into the body.       • The antibodies produced in the body against these antigens would neutralise the pathogenic agents during actual infection.                • The vaccines also generate memory – B and T-cells that recognise the pathogen quickly on subsequent exposure and kill the invaders with a massive production of antibodies.         Production of large scale of vaccine become possible through DNA recombinant technology which allowed the production of antigenic polypeptide(vaccine) in bacteria and yeast.     Hepatitis B vaccine is produced from yeast through DNA recombination technology for large scale immunisation. 

IMMUNITY:   • The ability of the host to fight the disease-causing organisms,   • conferred by the immune system.   .Immunity is of two types:   • Innate immunity   • Acquired immunity.  Innate immunity  • Non-specific type of defence,   • Present at the time of birth.   .Innate immunity is accomplished by providing different types of barriers to the entry of the foreign agents into our body.   • Innate immunity consists of four types of barriers.  These are —         • Physical barriers:                  Ø Skin                   Ø Mucus coating of the epithelium lining          • Physiological barriers:                  Ø Acid in the stomach,                  Ø saliva in the mouth,                  Ø tears from eye    cellular barriers:                     Ø Leukocytes (WBC) à polymorpho-nuclear leukocytes (PMNLneutrophils)                     Ø monocytes and                    Ø natural killer (type of lymphocytes)                   Ø macrophages in tissues          • Cytokine barr

              Parthenogenesis (Virgin birth) Modification of sexual reproduction An egg develops into a complete offspring without fertilization. It is monoparental. Parthenogenesis was discovered by Bonnet (1745). Parthenogenesis is found in many non vertebrates such as rotifers, aphids, bees and crustaceans. It also occur in a few vertebrates. Parthenogenesis is of two main types : Natural parthenogenesis :   It is a regular phenomenon in the life history at some animals. It may be three type.       Complete (Obligatory) parthenogenesis :            Males are absent,            females develop parthenogenetically,                    e.g., rotifers, Typhlina brahmina (small lizard, 15 cm long), Lacerta saxicola- armeniaca             (Caucasian Rock Lizard), Cnemidophorus (Whiptail Lizards of America).        Incomplete (cyclic) parthenogenesis :            Some animals have both sexual and parthenogenetic individuals, which may alternate.                    In these animals, female

  LESIONS IN VITAMIN D DEFICIENCY.  Deficiency of vitamin D may result from: i) reduced endogenous synthesis due to inadequate exposure to sunlight; ii) dietary deficiency of vitamin D; iii) malabsorption of lipids due to lack of bile salts such as in intrahepatic biliary obstruction, pancreatic insufficiency and malabsorption syndrome; iv) derangements of vitamin D metabolism as occur in kidney disorders (chronic renal failure, nephrotic syndrome, uraemia), liver disorders (diffuse liver disease) and genetic disorders; and v) resistance of end-organ to respond to vitamin D. Deficiency of vitamin D from any of the above mechanisms results in 3 types of lesions: 1. rickets in growing children; 2. osteomalacia in adults; and 3. hypocalcaemic tetany due to neuromuscular dysfunction. RICKETS .  The primary defects in rickets are: interference with mineralisation of bone; and deranged endochondral and intramembranous bone growth. The pathogenesis of lesions in rickets is bett

 HYPOTHYROIDISM 😩 Hypothyroidism is a hypometabolic clinical state resulting from inadequate production of thyroid hormones for prolonged periods, or rarely, from resistance of the peripheral tissues to the effects of thyroid hormones. The clinical manifestations of hypothyroidism, depending upon the age at onset of disorder, are divided into 2 forms: 1. Cretinism or congenital hypothyroidism is the development of severe hypothyroidism during infancy and childhood. 2. Myxoedema is the adulthood hypothyroidism. Cretinism A cretin is a child with severe hypothyroidism present at birth or developing within first two years of postnatal life. This is the period when brain development is taking place; in the absence of treatment the child is both physically and mentally retarded. The word ‘Cretin’ is derived from the French, meaning Christ-like because these children are so mentally retarded that they are incapable of committing sins. ETIOPATHOGENESIS.  The causes of conge

  Gout:  Gout is a disorder characterized by high levels of uric acid— the end product of purine catabolism—in blood (hyperuricemia), as a result of either the overproduction or underexcretion of uric acid.  The hyperuricemia can lead to the deposition of mono - sodium urate crystals in the joints, and an inflammatory response to the crystals, causing first acute and then progressing to chronic gouty arthritis.  Nodular masses of monosodium urate crystals (tophi) may be deposited in the soft tissues, resulting in chronic tophaceous gout (Figure 22.16).  Formation of uric acid stones in the kidney (urolithiasis) may also be seen. [Note: Hyperuricemia is typically asymptomatic and does not lead to gout, but gout is preceded by hyperuricemia.]  The definitive diagnosis of gout requires aspiration and examination of synovial fluid (Figure 22.17) from an affected joint (or material from a tophus) using polarized light microscopy to confirm the presence of needle-shaped mono - s

 INFLAMMATION😖 INTRODUCTION DEFINITION AND CAUSES.  Inflammation is defined asthe local response of living mammalian tissues to injury dueto any agent. It is a body defense reaction in order to eliminateor limit the spread of injurious agent, followed by removal of the necrosed cells and tissues. The agents causing inflammation may be as under: 1. Infective agents like bacteria, viruses and their toxins, fungi, parasites. 2. Immunological agents like cell-mediated and antigenantibody reactions. 3. Physical agents like heat, cold, radiation, mechanical trauma. 4. Chemical agents like organic and inorganic poisons. 5. Inert materials such as foreign bodies. Thus, inflammation is distinct from infection—while inflammation is a protective response by the body to variety of etiologic agents (infectious or non-infectious), while infection is invasion into the body by harmful microbes and their resultant ill-effects by toxins. Inflammation involves 2 basic processes with som

 This can be look like that 

  Tobacco-Related Diseases Tobacco contains numerous toxic chemicals having adverse effects varying from minor throat irritation to carcinogenesis. Some of the important constituents of tobacco smoke with adverse effects  The major diseases accounting for higher mortality in tobacco smokers include the following (in descending order of frequency): i) Coronary heart disease ii) Cancer of the lung iii) Chronic obstructive pulmonary disease (COPD). Besides above, smokers suffer higher risk of development of a few other cancers and non-neoplastic conditions as illustrated  CORONARY HEART DISEASE .  Cigarette smoking is one of the four major risk factors for myocardial infarction and acts synergistically with the other three—hypercholesterolaemia, hypertension and diabetes mellitus (Chapter 15). There is more severe, extensive and accelerated atherosclerosis of coronary arteries and aorta in smokers, possibly due to increased platelet aggregation and impaired lung functi