Gangrene And Apoptosis PDF

Gangrene Dr. Syeda Fakhra Waheed DVM, MPhil, Ph.D Pathology Post Doc. Molecular Biology  Gangrene It is the invasion of necrotic or dead tissue by the saprophytic bacteria (Bactria growing on dead tissues) Gangrene is mostly seen in lungs, intestine, mammary glands,...

Gangrene Dr. Syeda Fakhra Waheed DVM, MPhil, Ph.D Pathology Post Doc. Molecular Biology  Gangrene It is the invasion of necrotic or dead tissue by the saprophytic bacteria (Bactria growing on dead tissues) Gangrene is mostly seen in lungs, intestine, mammary glands, thigh muscles and body extremities Lungs; faulty drenching of medicine, medicine goes into lungs instead of stomach; improper insertion of stomach tube, again contents go into lungs, cause necrosis followed by gangrene Intestine; malposition or twisting of intestines, blood vessels are compressed, leading to necrosis followed by gangrene (saprophytic bacteria present in intestinal contents) Extremities; ear, nose, finger tips etc.. Injury caused by frost bite (extreme cold) leads to Coagulative necrosis, then invaded by saprophytes Senile gangrene; seen in old age, artiosclerosis (thickening and narrowing of arteries), reduced blood supply to body tissues, necrosis and then gangrene Diabetic gangrene; seen in diabetic patients, narrowing of arteries and more sugar content in body tissues, necrosis and gangrene occurs  Types of Gangrene Gangrene has two types; dry and moist Dry gangrene; seen in body extremities, necrotic tissue is dry, bacterial growth is slow, temperature of the extremities is also low Macroscopically, area is dry and appears mummified, the color depends upon the amount of iron sulphide formation, irons comes from degraded hemoglobin and bacterial putrefaction (decomposition) produces hydrogen sulphide, reaction between iron and hydrogen sulphide produces iron sulphide which is black in color, also know as pseudomelanosis (false melanin), putrid odor also present due to hydrogen sulphide Gangrene moves towards normal body parts, that’s why area or sometimes whole limb is removed (amputation) to save the life Microscopically; structureless necrotic area, densely pink stained, with numerous saprophytic bacteria  Moist Gangrene Occurs in internal body organs where is more moisture and high temperature is available Due to optimum conditions, growth of bacteria is very high More commonly seen in intestine, as a result, intestine ruptures, bacteria spread to other visceral organs, death occurs rapidly  Gangrene Dry Moist  Apoptosis Apoptosis (dropping off, G.), Pronounced as apotosis (one p silent) Also known as programmed cell death, or cell suicide Involves single cell or cluster of cells Apoptotic cells show cytoplasm intensely stained with eosin, and dense chromatin nuclear fragments (apoptotic bodies) These cells are often engulfed by phagocytic cells and destroyed Apoptosis is responsible for numerous physiological process in the body; destruction of RBCs, uterine involution in menstrual cycle and after pregnancy etc.. Apoptosis is also seen in pathological conditions or infectious diseases  Apoptosis (Necrobiosis) Embryogenesis Hormonal (endometrium during estrus cycle) Epithelial cells Tumor cells Virus infected cell  Mechanism of Apoptosis Signaling – Intrinsic programmed – Lack of growth factors – Specific ligand-receptor interaction (TNF) – Release of granzymes from cytotoxic T-cells – Mild injurious stimuli Control and Integration – Direct transmission of death signals by specific adaptor proteins to the execution mechanism – Regulation of mitochondrial permeability by members of the BCL-2 family of proteins and release of cytochrome c in the cytosol Execution by catabolic enzymes Removal of dead cells Differences Thank You