Sandra M. Cockfield, M.D.

• Professor
• Department of Medicine
• University of Alberta
• Medical Director
• Renal Transplant Program
• Walter C. Mackenzie Health Science Center
• Edmonton, Alberta, Canada

Events during incubation period:During the initial asymptomatic period (about 2 weeks) shot of antibiotics for sinus infection terramycin 250 mg overnight delivery, the Salmonella attach to the microvilli and penetrate the ileal mucosa of the small intestinereach lamina propria and submucosa antibiotics for dogs cost cheap 250 mg terramycin amex. Typhoid fever: Lipopolysaccharide endotoxin is responsible for leukopenia and splenomegaly antimicrobial nail polish 250 mg terramycin buy overnight delivery. They multiply in the lymph nodes and via the thoracic duct enter the bloodstream causing transient bacteremia antibiotics xanax interaction terramycin 250 mg order. They colonize reticuloendothelial tissues (liver bacteria 2 game terramycin 250 mg buy amex, gallbladder, spleen, bone marrow), where bacilli multiply further causing massive bacteremia (occurs towards the end of incubation period) disease clinically manifests. Bile is a good culture medium for the typhoid bacillus, and bacilli multiplies in the gallbladderbacilli are continuously shed through the bile into the intestine. Lamina propria:Macrophages containing bacteria, red blood cells (erythrophagocytosis) and nuclear debrisLymphocytes and plasma cellsNeutrophils within the superficial lamina propria. Typhoid ulcers: Oval oriented along the long axis of the bowel whereas tuberculous ulcers of small intestine are transverse. Extraintestinal Lesions Typhoid nodules: Systemic dissemination of the bacilli leads to formation of focal granulomas termed typhoid nodules. These nodules are composed of aggregates of macrophages (typhoid cells) containing ingested bacilli, red blood cells, and lymphocytes. Mesenteric lymph nodes: They are enlarged due to accumulation of macrophage, which contains typhoid bacilli. Liver: It shows small, scattered foci of hepatocyte necrosis replaced typhoid nodules. However, neutrophils do not form the main cellular infiltrate and this is reflected in the leukopenia with neutropenia and relative lymphocytosis in the peripheral blood. Enteric fever:Abdominal pain Onset is gradual and patients present with anorexia, abdominal pain, bloating, nausea, (hallmark symptom) vomiting, and diarrhea. Clinical Features Rose spots: these are small erythematous maculopapular lesions on the skin that fade on pressure appear on the chest and abdomen, which occur during second or third week. Extraintestinal complications: Encephalopathy, meningitis, seizures, endocarditis, myocarditis, pneumonia, and cholecystitis. Laboratory Diagnosis Isolation of Bacilli Blood culture: It is positive in first week of fever in 90% of patients and remains positive in second week till the fever subsides. Stool cultures: It is almost as valuable as blood culture and become positive in the second and third weeks. Urine culture: It reveal is the organism in approximately 25% of patients by third week. Other Tests Widal reaction: Classic Widal test measures antibodies against O and H antigens of S. Widal test (immunological reactions) become positive from end of the first week till fourth week. Other serologic tests: They are available for the rapid diagnosis of typhoid fever with a higher sensitivity. Primary Intestinal Tuberculosis Uncommon in the developed countries, but common in developing countries including India. Nowadays due to eradication of tuberculosis in cattle and pasteurization of milk, all intestinal tuberculosis are caused by Mycobacterium hominis. Morphology Predominant changes are in the regional mesenteric lymph nodes without any significant intestinal lesion. Gross Lymph nodes are enlarged, matted and caseous (tabes mesenterica)may heal by fibrosis and calcification. Secondary Intestinal Tuberculosis Mode of Infection Swallowing of sputum in patients with active pulmonary tuberculosis. Intestinal tuberculosis: Most common site is terminal ileum and ileocecal junction. Intestinal tuberculosis: Involved segment become thickened and serosal aspects shows tubercles. Microscopy It shows caseating tubercles and should be distinguished from Crohn disease in which granulomas are non-caseating. Shigella is an unencapsulated, nonmotile, facultative anaerobic gram-negative bacilli. They belong to the Enterobacteriaceae and are closely related to enteroinvasive E. Shigella species that cause colitis are classified into four major subgroups namely: dysenteriae (most virulent), flexneri, boydii, and sonnei. Mode of transmission: By ingestion through fecal-oral route or via fecally contaminated water and food. Shigella: Most virulent enteropathogens produce Shigella is the most virulent enteropathogens and ingestion of few (10 to 100 organisms) toxin that has cytotoxic, produces disease. Small intestinal infections do not occur unless the patient has disturbance in motility of intestine. In the colon, the bacteria penetrate the intestinal mucous epithelium and are taken up by M or microfold epithelial cellsproliferate inside the cytoplasm of these epithelial cells penetrate into the lamina propriaphagocytosed by macrophagesShigella induces apoptosis of macrophages causes inflammatory reaction loosen the intercellular barriers and damages surface epithelium leading to superficial ulcersallows entry of Shigella in the intestinal lumen to the colonocyte basolateral membrane. Shigella produces a toxin that has cytotoxic, neurotoxic, and enterotoxic effects. When inflammation is severe, ileus, toxic megacolon, gross hemorrhage, and perforation may develop. Characteristics of ulcer: Mucosa shows edema, ulceration and appears friable granular and hemorrhagic. Ulcers appear first on the edges of mucosal folds, perpendicular to the long axis of the colon. Bacillary dysentery: Predominantly involves mucosa of left colon and rectosigmoid area. Early-stage: It shows erosions and small aphthous ulcers (microulcers), with infiltration by neutrophils below the microulcers. Advanced stage:Necrosis of epithelial cells and the damaged mucosa is covered by purulent exudate (composed of detached epithelial cells, neutrophils, and red blood cells). Mucosa shows multiple superficial ulceration with intervening normal mucosa Amebiasis is an infection caused by protozoan Entamoeba histolytica (named so because of its lytic actions on involved tissue). Precyst stage: In the colon, the trophozoite develops into a cyst through an intermediate involve cecum and form termed the precyst. Mode of infection: It is acquired by fecal-oral route through ingestion of materials contaminated with human feces containing E. A Pathogenesis the amebic cysts are passed in the stool and the cysts can contaminate water, food, or fingers. Amebic cysts then colonize the epithelial surface of the colon and release trophozoites. Each cyst containing four nuclei divides to form four small, immature trophozoiteswhich then matures to full size. They may colonize any part of the large intestine, but most frequently in the cecum and ascending colon causing amebic colitis. Trophozoite attaches the colonic epithelial cell and invades crypts, and burrow laterally into the lamina propria. Microscopically appear as flask shaped amebic ulcer (diagrammatic) that damages the cell membrane and creates a superficial ulcer. Recruitment of neutrophils causes tissue damage and creates a flask-shaped ulcer with a narrow neck and broad base. Trophozoite may penetrate blood vessels and reach the liver to produce abscesses in about 40% of patients with amebic dysentery. Intestinal disease: It mainly involves the colon and ranges from asymptomatic colonization to severe invasive infections causing bloody dysentery. Histolytica: Trophozoite invades crypts and burrow laterally in the lamina propria to produce flaskshaped ulcer. The intestinal wall shows thickening due to inflammation (napkin-ring constriction) and may resemble colon cancer. Microscopically, it consists of granulation tissue, inflammatory cells, fibrosis and clusters of trophozoites. Clinical Features Intestinal amebiasis: It may be asymptomatic or to produce dysentery of varying severity. Amebic dysentery may present with abdominal pain, bloody diarrhea, or weight loss. Abscess cavity is filled with a dark brown, odorless, semisolid necrotic material, which resembles anchovy paste (sauce) in color and consistency. Spread of amebic liver abscess (refer page 463):Local spread: It may expand and rupture through the capsule of the livermay directly spread into the peritoneum, diaphragm, pleural cavity, lungs, or pericardium. Clinical features of amebic liver abscess: It may present with severe right upper quadrant pain, low-grade fever, and weight loss. The diagnosis is usually made by radiologic or ultrasound demonstration of the abscess, in conjunction with serologic testing for antibodies to E. High-grade neuroendocrine tumors are known as well-differentiated neuroendocrine carcinomas. Microscopy Composed of uniform cells forming islands, trabeculae, strands, glands, or sheets. Carcinoid tumors: Those locate inSmall intestine tend to be malignantAppendix almost always benign course. Immunohistochemical stains: Tumor cells are positive for endocrine granule markers, such as synaptophysin and Carcinoid tumor: Malignant potential chromogranin A. Carcinoid tumors confined to the intestine, secrete vasoactive substances, which are metabolized to inactive forms by the liver. Carcinoid syndrome develops when tumors secrete hormones into a non-portal venous circulation. Clinical features: Flushing of skin, sweating, bronchospasm, colicky abdominal pain, diarrhea, and right-sided cardiac valvular fibrosis. Carcinoid syndrome: Clinical symptoms are due to vasoactive substances secreted by tumor cells. Foregut carcinoid:Most common location is somachMostly argyrophilic (silver staining only with the addition of reducing agent)Produce low levels of serotonin. Foregut carcinoid tumorsSites: Stomach, duodenum and esophagusMetastasis rare and are cured by resection. Midgut carcinoid tumors Carcinoid tumor syndrome:Sites: Jejunum and ileum Develops with metastasis to liver/lung. Hindgut carcinoids Carcinoid syndrome: Flushing, diarrhea,Sites: wheezing and sweating. Appendix: Usually seen at the tip and are less than 2 cm in diameter and are benign. Rectal carcinoid: It tends to produce polypeptide hormones, but metastasis is uncommon. Concordance for dizygotic twins for both Crohn disease and ulcerative colitis is less than 10%. Environmental Factors Includes both the local microenvironment (intestinal microflora) and the nutritional environment. Intestinal Microflora/Microbiota Hygiene hypothesis: the gut lumen contains abundant commensal bacteria and its composition within individuals remains stable for several years. Abnormal intestinal defensins: Paneth cell granules contain antimicrobial peptides termed defensins, which normally protect the mucosa against adherent and invading bacteria. Defective mucosal immune responses (immune dysregulation): Immunological abnormality have been observed in both innate (macrophage and neutrophil) and acquired (T and B cell) immunity. Normal regulatory immune response of gut mucosa: It is very powerful and prevents immunologic/inflammatory response against the dietary antigens and the commensal microbiota. The various events are: Transepithelial flux of luminal bacterial components: Bacterial components/antigens within the intestinal microbiota pass between leaky epithelial cells or enter the lamina propria through ulcerated mucosa. This causes further increases in the entry of bacterial components into the lamina propria. The above mentioned pathways occur in all normal individuals exposed to an inflammatory insult. Crohn disease: Commonly in the terminal ileum, but can involve any portion of the gastrointestinal tract. Number of lesions: Usually multiple and each lesion is sharply demarcated from intervening normal bowel giving rise to characteristic skip lesions. Multiple lesions may coalesce longitudinally to formelongated, linear or serpentine (snake-like)/train track/ rake ulcers oriented along the axis of the bowel. External surface/serosa: It appears red, opaque, hyperemic and covered with serosal exudate producing serositis. When the disease shows extensive transmural involvement, fat may encircle around the antimesenteric serosal surface producing a pattern known as creeping fat. Crohn disease: Radiologically characteristic string sign is due to only a trickle of contrast medium passing through the narrowed affected segment. Mucosal ulcers and inflammation: They appear as small, superficial called as aphthous ulcers. Both mucosa and submucosa shows edema and an increase in the number of lymphocytes, plasma cells, and macrophages. These neutrophils may infiltrate and damage crypt epithelium and are often associated with crypt destruction. Distortion of mucosal crypt architecture: Normally, crypts are straight and parallel to each other. Repeated cycles of crypt destruction and regeneration lead to bizarre branching shapes and unusual orientations to one anotherreferred as distortion of mucosal crypt. Pseudopyloric metaplasia: It is characterized by the occurrence of glands, which appear like those in the gastric antrum may be seen in the involved segment of the intestine.

Janjwal antibiotic resistance who quality terramycin 250 mg, Troponin elevation in patients with various tachycardias and normal epicardial coronaries antibiotic for sinus infection terramycin 250 mg purchase without a prescription, Indian Pacing Electrophysiol bacteria mod minecraft 125 terramycin 250 mg purchase fast delivery. Cervellin antibiotic resistance google scholar terramycin 250 mg with visa, Laboratory diagnosis of acute pancreatitis: in search of the Holy Grail antibiotics muscle pain terramycin 250 mg purchase mastercard, Crit. Younossi, When and how to evaluate mildly elevated liver enzymes in apparently healthy patients, Cleve. Monosaccharides are polyhydroxy compounds that also contain carbonyl functional groups, namely an aldehyde or ketone. The structure of carbohydrates, with the exception of dihydroxyacetone, contains at least one asymmetrical or chiral carbon atom giving rise to stereoisomers. The number of stereoisomers or enantiomers for a given carbohydrate is determined by 2n, where n is the number of chiral carbons. D- and L- designation of a monosaccharide is based on the chiral carbon located farthest from the carbonyl. In the Fischer projection, the D-monosaccharide has a hydroxyl group attached to the chiral carbon, on the right-hand side. Aldoses and pentoses are the most abundant monosaccharides, and in humans, they are D-stereoisomers. Stereoisomers that are not mirror images of each other are known as diastereoisomers; examples are D-ribose and D-arabinose. Diastereoisomers that differ by only a single chiral carbon atom are known as epimers; examples are D-glucose and D-galactose. In aqueous solutions, stable forms of monosaccharides of five or more carbon atoms exist as cyclic structures, which are formed due to reversible chemical reactions between a hydroxyl group and carbonyl group. In the process of cyclization, the carbonyl carbon becomes a chiral atom and is known as an anomeric carbon atom. The resulting two diastereoisomers are known as anomers, designated as - or -structures. In aqueous solutions, the - and -forms undergo interconversion and reach a stable ratio of anomers; this process is known as mutarotation. The conformational structural formulae of ring structures of monosaccharides are accurate representations in aqueous solutions. The physiologically important monosaccharide derivatives include sugar alcohols, sugar acids, amino sugars, sugar phosphates, and deoxysugars. Glycosides are formed when the hydroxyl group linked to an anomeric carbon atom condenses with the hydroxyl group of a second molecule with the elimination of water. Nutritionally and physiologically important disaccharides include sucrose, maltose, and lactose. A therapeutically useful nonabsorbable disaccharide is lactulose, which is used in the management of hepatic encephalopathy due to ammonia toxicity to the central nervous system. The chemosensory perception of the sweet taste of sucrose and other nonsucrose molecules is mediated by G-proteincoupled receptors located on the sensory cells of the tongue, ionotropic channels, and generation of electrical impulses. The nonsucrose synthetic sweeteners are varied in structure and have therapeutic applications in the management of diabetes and obesity. If the monosaccharides are all the same, they are known as homopolysaccharides; and if they are different, they are known as heteropolysaccharides. The three most important homopolysaccharides are glycogen, starch, and cellulose, and they contain glucose units. In both glycogen and starch, which is derived from plants, the glycosidic linkages are (1-4) and (1-6). In cellulose, a nondigestible carbohydrate in humans, the linkages between glucose units are (1-4). Cellulose and other indigestible polysaccharides and a nonpolysaccharide component, lignin, constitute dietary fiber and provide fecal mass. Dietary fiber is an essential component in the maintenance of optimal health and nutrition. They are the primary source of energy in animal cells; carbohydrates are synthesized in green plants from carbon dioxide, water, and solar energy. They provide the skeletal framework for tissues and organs of the human body, and serve as lubricants and support elements of N. They confer biological specificity and provide recognition elements on cell membranes. In addition, they are components of nucleic acids and are found covalently linked with lipids and proteins. However, a large number of compounds are classified as carbohydrates even though they do not have this empirical formula; these compounds are derivatives of simple sugars. Carbohydrates may be classified as monosaccharides, oligosaccharides, or polysaccharides; the term saccharide is derived from the Greek word for sugar. Sucrose and lactose are disaccharides, since they are each made up of two monosaccharide units. Polysaccharides, also known as glycans, are polymers that may contain many hundreds of monosaccharide units. The designation of D or L, given to a monosaccharide with two or more asymmetrical centers, is based on the configuration of the asymmetrical carbon atom located farthest from the carbonyl functional group. Thus, if the configuration at that carbon is the same as that of D-glyceraldehyde (with the hydroxyl group on the right-hand side), it belongs to the D series. A similar relationship exists between L-glyceraldehyde (with the hydroxyl group on the lefthand side) and the L series of monosaccharides. The optical rotation of a monosaccharide with multiple asymmetrical centers is the net result of contributions from the rotations of each optically active center. Thus, the prefix D or L provides no information with regard to optical rotation; it indicates only the configuration around the asymmetrical carbon atom located farthest from the carbonyl carbon. The numbering system for monosaccharides depends on the location of the carbonyl carbon (or carbon atom in the most oxidized state), which is assigned the lowest possible number. For glucose (an aldohexose), carbon C1 bears the carbonyl group and the farthest asymmetrical carbon atom is C5 (the penultimate carbon), the configuration which determines the D and L series. For fructose (a ketohexose), C2 bears the carbonyl group, and C5 is the highest numbered asymmetrical carbon atom. The simplest monosaccharides are the two trioses: glyceraldehyde (an aldotriose) and dihydroxyacetone (a ketotriose). Four-, five-, six-, and seven-carbon-containing monosaccharides are called tetroses, pentoses, hexoses, and heptoses, respectively. All monosaccharides, with the exception of dihydroxyacetone, contain at least one asymmetrical or chiral carbon atom, and therefore two or more stereoisomers are possible for each monosaccharide depending on the number of asymmetrical (chiral) centers it contains. In general, the total number of possible isomers with a compound of n asymmetrical centers is 2n. Thus, for aldohexoses having four asymmetrical centers, 16 isomers are possible, 8 of which are mirror images of the other 8 (enantiomers). Most of the physiologically important isomers belong to the D series, although a few L-isomers are also found. In later discussions, the designation of D and L is omitted, and it is assumed that a monosaccharide belongs to the D series unless it is specifically designated an L-isomer. Of the D series of aldohexoses, three are physiologically important: D-glucose, D-galactose, and D-mannose. D-galactose and D-mannose are not epimers, since they differ in configurations around both C2 and C4. D-fructose, one of eight 2-ketohexoses, is the physiologically important ketohexose. Cyclic forms of D-glucose are formed by the hemiacetal linkage between the C1 aldehyde group and the C4 or C5 alcohol group. The thick line of the structure projects out toward the observer and the upper edge (thin line) projects behind the plane of the paper. Aldohexoses exist in solutions mainly as sixmembered pyranose ring forms, since these forms are thermodynamically more stable than furanose ring forms. Cyclization of a monosaccharide results in the formation of an additional asymmetrical center, known as the anomeric carbon, when the carbon of the carbonyl group reacts with the C5 hydroxyl group. Aldohexoses in their cyclic forms have five asymmetrical centers and, therefore, 32 stereoisomers. In other words, each of the 16 isomers that belong to the D or L series has two anomeric forms. The systematic names for these two anomers are -D-glucopyranose and -D-glucopyranose. Carbon atoms of the ring are not explicitly shown but occur at junctions of lines representing bonds. Sometimes the hydrogen atoms are also omitted and are presumed to exist wherever a bond line ends without a specified group. Interconversion of - and -forms can be followed in a polarimeter by measuring the optical rotation of D-glucopyranose (D-glucose) in aqueous solutions. However, over a period of a few hours at room temperature, the specific rotation of both forms in aqueous solution changes and attains a stable value of 152. This change in optical rotation, known as mutarotation, is characteristic of sugars that form cyclic structures. Thus, the change in structure can occur in solution and attain equilibrium, which favors the formation of more stable (lowest energy) forms. D-fructose, a ketohexose, can potentially form either a five-membered (furanose) or a six-membered (pyranose) ring involving formation of an internal hemiketal linkage between C2 (the anomeric carbon atom) and the C5 or C6 hydroxyl group, respectively. In aqueous solution at equilibrium, fructose is present predominantly in the -fructopyranose form. However, when fructose is linked with itself or with other sugars, or when it is phosphorylated, it assumes the furanose form. Fructose 1,6-bisphosphate is present in the -fructofuranose form, with a 4:1 ratio of - to -anomeric forms. Fructose is a major constituent (38%) of honey; the other constituents are glucose (31%), water (17%), maltose (a glucose disaccharide, 7%), sucrose (a glucoseructose disaccharide, 1%), and polysaccharide (1%). The individual monosaccharides are better quantitated by specific procedures, such as an enzymatic procedure. A reaction frequently used in the determination of carbohydrate structure, and for its identification in tissue preparations, is the periodate reaction. The vicinal glycols on periodate oxidation yield a dialdehyde; this reaction is quantitative. Periodate cleavage of glycogen (a polyglucose) yields a polyaldehyde that can be coupled to a visible dye reaction. Some physiologically important monosaccharide derivatives include sugar alcohols, sugar acids, amino sugars, sugar phosphates, deoxy sugars, and sugar glycosides. Sialic Acids Sialic acids are derivatives of a nine-carbon-containing monosaccharide, ketonanose, known as neuraminic acid. They typically occur as the terminating units of oligosaccharide side chains of some glycoproteins and glycolipids of mammalian cell membranes, as well as on secreted glycoproteins (Chapter 9). In humans, due to deletion of the gene for the hydroxylase enzyme, N-glycolylneuraminic acid (Neu5Gc) is absent. However, Neu5Gc is found in foods derived from poultry, fish, red meat, and milk products, and has been shown to be metabolically incorporated into cell surface membranes of humans. Recent studies have revealed that the incorporation of this nonhuman glycan provides highaffinity receptors for a cytotoxic protein secreted by Shiga toxigenic Escherichia coli. The gastrointestinal disease (see Chapter 11 for mechanism) and hemolytic uremic syndrome caused by the infection of this toxigenic E. Maltose is composed of two glucose residues joined by an -glycosidic linkage between C1 of one residue and C4 of the other residue [designated (1-4)]. In maltose, the second sugar residue has an unsubstituted anomeric carbon atom and therefore can function as a reducing agent, as well as exhibit mutarotation. In trehalose, two glucose residues are joined by an -linkage through both anomeric carbon atoms; therefore, the disaccharide is not a reducing sugar, nor does it exhibit mutarotation. Lactose, synthesized only by secretory cells of the mammary gland during lactation, is a disaccharide consisting of galactose and glucose. Lactose is a reducing sugar and exhibits mutarotation by virtue of the anomeric C1 of the glucose residue. Lactulose is a synthetic disaccharide consisting of galactose and fructose linked through a -linkage between C1 of galactose and C4 of fructose. It is used in the treatment of some forms of chronic liver disease (such as hepatic encephalopathy) in which the ammonia content in the blood is elevated (hyperammonemia). Normally, ammonia produced in the gastrointestinal tract, principally in the colon by microbial action, is transported to the liver via the portal circulation and inactivated by conversion to urea (Chapter 15). Oral administration of lactulose relieves hyperammonemia by microfloral conversion in the colon to a variety of organic acids. Reduction of luminal pH may additionally promote a microflora that causes a decrease in the production of ammonia, as well as an increase in its utilization. The osmotic activity of the disaccharide and its metabolites causes an osmotic diarrhea, which is useful in eliminating toxic waste products. Compared to lactulose, lactitol has the advantage of higher palatability and fewer side effects. Ammonia production in the colonic lumen by urease-producing bacteria can be reduced by administering antibiotics such as neomycin or metronidazole. The therapeutic effect of the combined use of a nonabsorbable disaccharide and an antibiotic may result from the metabolism of the disaccharide by antibiotic-resistant bacteria. Sucrose, a widely occurring disaccharide found in many plants (cane sugar and beet sugar), consists of glucose and fructose moieties linked together through C1 of glucose and C2 of fructose. The perception of sweetness is mediated by taste buds submerged in the tongue and oral mucous membranes. The taste bud, a pear-like organ, consists of sensory cells (taste cells) interwoven with a branching network of nerve fibers. Sensory cells have a short lifespan of about 10 days, and new cells are derived from basal cells that continually undergo mitosis. Sensory cells contain microvilli (thin hair-like projections on the surface of the cells).

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In aspirated joint fluids virus treatment buy terramycin online pills, birefringent urate crystals can be seen in the polarized light microscope antibiotic resistance threat terramycin 250 mg lowest price, which is used in definitive diagnosis antibiotic of choice for strep throat terramycin 250 mg buy. Drugs used to lower serum urate concentrations include probenecid antibiotic unasyn terramycin 250 mg buy overnight delivery, sulfinpyrazone antibiotic overuse terramycin 250 mg buy visa, and allopurinol. Colchicine depolymerizes microtubules and structures (such as the mitotic spindle) consisting of microtubules. It is effective in decreasing pain and the frequency of attacks, but its mechanism of action is obscure. Allopurinol, an analogue of hypoxanthine, inhibits xanthine oxidase and reduces formation of xanthine and uric acid. It is used in patients who exhibit undesirable toxic reaction to allopurinol therapy and in chronic renal insufficiency. Rapid removal of uric acid in serum is also accomplished by administration of recombinant rasburicase, which converts uric acid to soluble allantoins. Rasburicase is used in the treatment of hyperuricemia of acute tumor lysis syndrome (Clinical Case Study 25. Drugs that increase uric acid excretion in humans include probenecid, which is effective in the regulation of hyperuricemia and the resolution and prevention of tophi, and sufinpyrazone, which has similar effects. Both agents are weak organic acids and probably act as competitive inhibitors of tubular reabsorption of uric acid. Dietary and Lifestyle Factors Serum urate levels can be lowered by dietary and lifestyle changes. These include correction of obesity, avoidance of ethanol consumption, and avoidance of high-purine foods. These abnormalities include mental retardation, spasticity (increased muscle tension resulting in continuous increase of resistance to stretching), choreoathetosis (characterized by irregular, jerky, or explosive involuntary movements, and writhing or squirming, which may involve any extremity or the trunk), and a compulsive form of self-mutilation. Such patients do not usually develop gouty arthritis early in life, but do exhibit uric acid crystalluria and stone formation. The most significant abnormality identified in neurotransmitter systems is in the dopaminergic pathway (Chapter 30). Hershfield, Immunodeficiency diseases caused by adenosine deaminase and purine nucleoside phosphorylase deficiency. This autosomal recessive trait results in inability to salvage adenine, which accumulates and is oxidized to 2,8-dihydroxyadenine by xanthine oxidase. The main clinical abnormality is the excretion of 2,8-dihydroxyadenine as insoluble material (gravel) in the urine. Both enzymes function in the conversion of adenosine and deoxyadenosine to hypoxanthine. This cycle plays an important role in energy production in skeletal muscle during exercise. In contrast, in de novo purine nucleotide biosynthesis, ribose 5-phosphate is an integral part of the earliest precursor molecule. In the biosynthesis of both pyrimidine and urea (or arginine) (Chapter 15), carbamoyl phosphate is the source of carbon and nitrogen atoms. In pyrimidine biosynthesis, carbamoyl phosphate serves as donor of the carbamoyl group to aspartate with the formation of carbamoyl aspartate. In urea synthesis, the carbamoyl moiety of carbamoyl phosphate is transferred to ornithine, giving rise to citrulline. In eukaryotic cells, two separate pools of carbamoyl phosphate are synthesized by different enzymes located at different sites. It supplies carbamoyl phosphate for pyrimidine nucleotide biosynthesis and uses the amido group of glutamine as nitrogen donor. Several mechanisms have been proposed to explain how the increase in flux is responsible for the maintenance of appropriate energy levels during exercise. For example, pyrimidine nucleotides are involved in the biosynthesis of glycogen (Chapter 14) and of phospholipids (Chapter 17). Biosynthesis of pyrimidine nucleotides can occur by a de novo pathway or by the reutilization of preformed pyrimidine bases or ribonucleosides (salvage pathway). The second gene codes for dihydro-orotate dehydrogenase, which is located on the outer side of the inner mitochondrial membrane. Dihydro-orotate, the product of Pyr 1, passes freely through the outer mitochondrial membrane and converts to orotate. Use of multifunctional polypeptides is very efficient, since the intermediates neither accumulate nor become consumed in side reactions. Other pathways in eukaryotic cells, such as fatty acid synthesis, occur on multifunctional polypeptides. Pyr 5,6 5 5, orotate phosphoribosyltransferase; 6, orotidine-50 -monophosphate decarboxylase. Biosynthesis of purine and pyrimidine nucleotides requires carbon dioxide and the amide nitrogen of glutamine. Both use an amino acid "nucleus"-glycine in purine biosynthesis and aspartate in pyrimidine biosynthesis. Thymidine nucleotide deficiency can also be induced by competitive inhibitors of dihydrofolate reductase. A similar toxic manifestation due to deficiency of thiopurine metabolizing enzyme was discussed earlier. The study of the role of genetic inheritance that leads to variations in drug response is known as pharmacogenomics. They are converted to nucleosides by nucleoside phosphorylases and then to nucleotides by appropriate kinases. All of these compounds require conversion to appropriate nucleotides before they become active. An antifungal agent, flucytosine (5fluorocytosine), acts through conversion to 5-fluorouracil by cytosine deaminase in the fungal cells. Idoxuridine (iododeoxyuridine), another halogenated pyrimidine derivative, is used in viral infections. The 20 -hydroxyl group of the arabinose moiety is in a trans position with respect to the 30 hydroxyl group (instead of in a cis position, as in the ribose) and causes steric hindrance to rotation of the base around the nucleoside bond. Phosphorylated derivatives of cytarabine inhibit nucleic acid synthesis as well as being incorporated into nucleic acids. During rapid proliferation of cells, either as a normal physiological process or in pathological processes. These results suggest that adenosine inhibits the conversion of orotic acid to orotidine-50 -monophosphate. Adenosine deaminase reduces the toxic effect of adenosine by converting it to inosine. This inhibition of formation of pyrimidine nucleotides in the presence of excess purine nucleosides and nucleotides has been termed pyrimidine starvation. In contrast to purine catabolism, pyrimidine catabolism yields highly soluble end products. Orotic aciduria is characterized by failure of normal growth and by the presence of hypochromic erythrocytes and megaloblastic bone marrow, none of which is improved by the usual hematinic agents. Treatment with uridine (2 g/d) results in marked improvement in the hematological abnormalities, in growth and development, and in decreased excretion of orotic acid. These patients are pyrimidine auxotrophs and require an exogenous source of pyrimidine just as all humans need vitamins, essential amino acids, and essential fatty acids. Deficiency of folate or vitamin B12 can cause hematological changes similar to hereditary orotic aciduria. This interrelationship Nucleotide Metabolism Chapter 25 487 Folate is directly involved in thymidylic acid synthesis and indirectly involved in the metabolic functions of vitamin B12. Orotic aciduria without the characteristic hematological abnormalities occurs in disorders of the urea cycle that lead to the accumulation of carbamoyl phosphate in mitochondria. The carbamoyl phosphate exits from the mitochondria and augments cytosolic pyrimidine biosynthesis. Treatment with allopurinol or 6-azauridine also produces orotic aciduria as a result of inhibition of orotidine-50 -phosphate decarboxylase by their metabolic products. Synopsis A 54-year-old man with four arthritic attacks during the previous year was found to have serum urate levels of 7. His serum renal function test was within the reference interval, with creatinine of 1. The concern was what course of medical options to undertake to correct his hyperuricemia. In order to prevent acute attacks, daily colchicine administration was used as prophylaxis. The patient was advised to refrain from intake of alcohol and excessive consumption of meat and seafood. Acute inflammatory gout disease is caused by monosodium urate crystals undergoing phagocytosis in the synovial joint fluid. This process leads to activation of the inflammatory response, with production and release of several inflammatory mediators, leading to severe pain. The acute attacks are treated with colchicine, glucocorticoids, and/or nonsteroidal anti-inflammatory drugs. For patients who cannot tolerate allopurinol, a nonpurine xanthine oxidase inhibitor like febuxostat may be considered. Hyperuricemia can also be treated with uricosuric drugs: probenecid, sulfinpyrazone, and benzbromarone. If conventional treatments cannot correct hyperuricemia, a pegylated porcine recombinant uricase is used, which converts uric acid to soluble allantoin. Note that uricase is not present in humans, and thus, the relatively insoluble uric acid is the end product of purine catabolism. Synopsis An 8-year-old male with cervical lymphadenopathy, malaise, and repeated vomiting was brought to the emergency department. Laboratory studies revealed he had hyperphosphatemia and acute renal failure, and later he was diagnosed with acute tumor lysis syndrome. Excessive cell destruction of tumor cells during chemotherapy causes cellular contents to be spilled into the bloodstream, causing hyperuricemia, hyperkalemia, hyperphosphatemia, and acute kidney failure. Acute kidney failure results from deposition of calcium phosphate and urate crystals in the renal tubules, and is assessed by measurement of serum creatinine levels. Management of tumor lysis syndrome and its acute toxic effects involves intravenous fluid administration, renal dialysis, and administration of rasburicase. Rasburicase is a recombinant uricase (urate oxidase), which converts uric acid to a more soluble form, allantoin. The predominant Hb after one year of age is HbA, a tetramer (22), and each subunit contains a heme group with an iron atom in the Fe21 state. Myoglobin is a monomer that provides O2 during muscle contraction and binds more tightly to O2 than Hb. It is synthesized in the juxtatubular interstitial cells of the renal cortex in response to hypoxemia. Recombinant erythropoietin preparations are used in the treatment of anemia patients with chronic kidney disease who are undergoing dialysis. Genetic defects of deletions and point mutations in the - and -globin genes lead to decreased chain synthesis, resulting in - and -thalassemia syndromes, respectively. These syndromes are clinically heterogeneous and cause ineffective erythropoiesis and hemolysis. Sickle cell disease, which is due to point mutation leading to substitution of glutamate to valine in the -chain at the 6th position, yields HbS. The treatment is palliative; it also uses hydroxyurea, which promotes HbF synthesis, ameliorating the symptoms. Reawakening of HbF production by regulating erythroid transcription factors is under investigation as a possible therapeutic intervention in the treatment of -thalassemia syndromes, sickle cell, and malaria diseases. Elevated Hb F levels in the erythrocytes thwarts the susceptibility of malarial parasites. When Fe21 of the heme group is converted to Fe31, the Hb is converted to methemoglobin, and it is not an oxygen carrier. Methemoglobinemia can occur due to defects in the enzymes, converting Fe31 to Fe21, or specific amino acid substitutions in the heme pocket of the - and -globin chain or acquired causes. The treatment requires blood transfusion and in some cases methylene blue, which, in its reduced form, converts metHb to Hb. The -gene complex consists of one functional gene and two functional genes, and the -gene complex consists of five functional genes:, G, A, and. The genetic and regulatory mechanisms of -globin gene cluster expression are being explored to stimulate HbF production. Elevated hemoglobin F production attenuates the symptoms of subjects with sickle cell diseases and -thalassemia syndromes. Polycythemia vera (primary polycythemia, a disorder of increased erythrocytes) and Hb are associated with an activating mutation (V617F) of tyrosine kinase Jak-2. The intracellular signaling of Jak-2 V617F mutant undergoes constitutive activation independent of ligand. In about 60% of essential thrombocytosis and primary myelofibrosis, the Jak-2 V617F mutation is found. Treatment for these disorders is palliative or hematopoietic stem cell transplantation for selected patients. Hemoglobin is the predominant protein in the red blood cell and is responsible for transporting oxygen, carbon dioxide, and protons between the lungs and tissues. The study of hemoglobin has led to detailed knowledge of how oxygen and carbon dioxide transport is accomplished and regulated, and has provided insight into the functioning of other allosteric proteins (Chapter 6).

Recruits two enzymes (histone deacetylases and histone methyltransferases) that block the transcription bacteria genus 250 mg terramycin order overnight delivery. It plays main role in p53: Guardian of the maintaining the integrity of the genome and thus known as guardian of the genome or genome antibiotics for acne and alcohol buy terramycin 250 mg. Method of inactivation of p53 gene and associated tumors: Most cancers have defect in p53 gene antibiotics for sinus infection in canada 250 mg terramycin buy with visa. Homozygous loss of p53: It is characterized by cells having one normal p53 allele and one mutant allele antimicrobial fabric buy terramycin discount. Homozygous loss of p53 occurs in leading causes of cancer death 100 oz antimicrobial replacement reservoir terramycin 250 mg purchase, namely carcinoma of the lung, colon, and breast. It has germ line mutations in one p53 but their tumors shows mutations of both alleles. Heterozygous loss: Many cancers show inactivating mutations of both p53 alleles and the cell does not contain p53 protein. Location, function and tumors associated with few selected tumor suppressor genes are presented in Table 7. Mutations in the genes that regulate apoptosis may result in accumulation of neoplastic cells. Reduced apoptosis may be due to activation of either antiapoptotic proteins or reduced proapoptotic activity. Activation of antiapoptotic Bcl-2: Example, follicular lymphomas (about 85%) show a characteristic chromosomal translocation, t(14;18), causing overexpression of the antiapoptotic Bcl-2 protein. Neoplastic B lymphocytes are protected from undergoing apoptosis and survive for long periods. Bcl-2: An antiapoptotic gene activated by t (14;18) translocation in majority of follicular B cell lymphoma. Most normal cells have a capacity to undergo cell division for about 60 to 70 times. Increased incidence of Telomere (refer page 36-37) is the special structure present at the ends of chromosomes. Mutations in these tumor suppressor genes can lead to loss of inhibitory control at checkpoints. Uncontrolled Replication Reactivation of telomerase: During the course of repeated cell cycles, there is progressive shortening of telomeres, which is prevented by an enzyme called telomerase. Telomere maintenance is seen in many types of cancers and is mostly due to up-regulation of the enzyme telomerase. Vascularization of tumor: Solid tumors cannot grow without vascularization and is achieved mainly by neoangiogenesis (common) in which new vessels sprout from existing capillaries. Effects of neovascularization:Supplies nutrients and oxygenSecretion of growth factors by newly formed endothelial cells, which stimulate the growth of adjacent tumor cells. These Microsatellites: Tandem repeats of one to six nucleotides found in the genome. Microsatellite instability: One of the characteristic of patients with mismatch-repair defects is microsatellite instability. Microsatellites are tandem repeats of one to six nucleotides found throughout the genome. Nucleotide excision repair: Example, xeroderma pigmentosum It is an inherited disorder of defective nucleotide excision repair gene. It is a necessary process in meiosis and involves exchange of genetic information. Exposure to ionizing radiation significantly increases the rate of breakage in chromosomes. Disorders associated with recombination repair genes include Bloom syndrome, ataxia-telangiectasia, and Fanconi anemia. List major chemical carcinogens and describe in detail chemical Sir Percival Pott (London surgeon) first related scrotum skin cancer in chimney sweeps to carcinogenesis. Based on this, a rule was made that chimney sweep members must bathe daily and this public health measure controlled scrotal skin cancer. Japanese investigators (Yamagiva and Ichikawa) experimentally produced skin cancers in rabbits by using coal tar. Direct-acting chemical agents: Do not require metabolic conversion to become carcinogenic, but are weak carcinogens. Direct-acting Agents Alkylating agents: Solid Direct-acting chemical agents do not require metabolic conversion to become carcinogenic, and hematological but most of them are weak carcinogens. Indirect-acting Agents (Procarcinogens) these chemicals require metabolic activation for conversion to an active ultimate carcinogen. Polycyclic aromatic hydrocarbons: They are the most potent and extensively studied indirect-acting chemical carcinogens. Cigarette smoke: Polycyclic aromatic hydrocarbons are formed during hightemperature combustion of tobacco in cigarette smoking responsible for lung cancer in cigarette smokers. Alkylating Agents-propiolactone Anticancer drugs (cyclophosphamide, chlorambucil, nitrosoureas, etc. Polycyclic and Heterocyclic Aromatic HydrocarbonsBenz[a]anthracene Benzo[a]pyrene Dibenz[a,h]anthracene 7,12-Dimethylbenz[a]anthracene 3-Methylcholanthrene 2-Naphthylamine (-naphthylamine) Benzidine 2-Acetylaminofluorene Dimethylaminoazobenzene (butter yellow) 2. Aromatic amines: Bladder and liver cancers Animal fats: It may produce it during the process of broiling meats. Example: Polyvinyl chloride (used plastic industry) is metabolized to an epoxide causes hepatic angiosarcomas. However, can be detoxified immediately by conjugation with glucuronic acid in the liver. The conjugated metabolite is excreted in the urine and deconjugated in the urinary tract by the enzyme glucuronidase. The urothelium is thus exposed to the active carcinogen (reactive hydroxylamine) which may cause bladder cancer. Natural microbial product Aflatoxin: Hepatocellular Aflatoxin B1Source: Aflatoxin B1 is a natural product of Aspergillus flavus, a mold which grows on carcinoma improperly stored grains and peanuts. Metals: Compounds like arsenic, nickel, lead, cadmium, cobalt, chromium and beryllium can produce cancer. Asbestos: Inhalation of asbestos fibers results in asbestosis, pleural plaques, mesothelioma and carcinoma of the lung. Detection of carcinogenicity of a chemical: Mutagenicity testing of chemical is done by Ames test: To detect Ames test. The appearance of frameshift mutations and base-pair substitutions in a culture carcinogenicity of a chemical. Multistep carcinogenesis Molecular targets of chemical carcinogens: Most chemical carcinogens are mutagenic. A Most chemical carcinogens are mutagenic mutagen is an agent, which can permanently alter the genetic constitution of a cell. Once the tumor process is started, it does not require the continued presence of the carcinogen. Initiation: It is the first important step that develops from exposure of cells to a sufficient dose of a carcinogenic agent (initiator). After exposure of a cell mutated) cells to enter into the cell cycle cell proliferation. Unlike initiators, the to initiator, promoters cellular changes produces by promoters are reversible. Differences between initiators Examples of promoters includes: phorbol esters, hormones, phenols, and drugs. Progression: Continuous proliferation of initiated cells leads to secondary genetic abnormalities tumor growth becomes independent of the initiator or the promoter. Cancer: Final result of the different steps is the development of neoplasminvasion metastases. Examples: the morphologic sequence of hyperplasia, dysplasia, and carcinoma in situ found in epithelium. Many viruses have been proved to be oncogenic in animals, but only a few have been associated with human cancer. Tumor caused: Adult T-cell leukemia/lymphoma-develops after a long latent period (20 to 50 years). Mode of infection: (1) sexual intercourse, (2) blood products, and (3) breast feeding. Combined action of E6 and E7: They induce centrosome duplication and genomic instability. Patients may manifest as a shortlived infectious mononucleosis or develop few human cancers. The virus becomes latent inside the B cells are transformed or "immortalized" so that they are capable of proliferation indefinitely. Immunologically mediated chronic inflammation: It causes death of the hepatocytes. Compensatory liver cell regeneration: It is aided by a several growth factors and cytokines produced by activated immune cells of inflammation. Merkel Cell Polyoma Virus Merkel cell carcinoma Adult T-cell leukemia/lymphoma Lesions Neoplasms due to Helicobacter pylori: 1. Aflatoxins B1 produced by Aspergillus flavus is a potent carcinogen responsible for hepatocellular carcinoma. Parasites Two parasites which can causes tumor are: Schistosoma is strongly implicated in carcinoma of urinary bladder (usually of squamous cell type). Clonorchis sinensis (Chinese liver fluke) lodges in the bile ducts produces an inflammatory reaction, epithelial hyperplasia and sometimes adenocarcinoma of the bile ducts (cholangiocarcinoma). Estrogen Endometrial carcinoma: It may develop in females with estrogen-secreting granulosa cell tumor of ovary or those receiving exogenous estrogen. Adenocarcinoma of vagina: Increased frequency of adenocarcinoma of vagina is observed in daughters of mothers who received estrogen during pregnancy. Abnormal vascularity of tumor: Estrogens can make existing tumors abnormally vascular. Hormone-dependent Tumors Prostatic carcinoma usually responds to administration of estrogens or castration. Radiation has also additive or synergistic effects with other potential carcinogenic agents. Tumors caused: Skin cancer namely (1) squamous cell carcinoma, (2) basal cell carcinoma, and (3) malignant melanoma. Ionizing Radiation Electromagnetic (X-rays, rays) and particulate (particles, particles, protons, neutrons) radiations are all carcinogenic. Atomic bomb explosion: Survivors atomic bomb explosion (dropped on Hiroshima and Nagasaki)increased incidence of leukemiasmainly acute and chronic myelogenous leukemia after about 7 years. Therapeutic radiation: (1) papillary carcinoma of the thyroid follows irradiation of head and neck and (2) angiosarcoma of liver due to radioactive thorium dioxide used to visualize the arterial tree. Different laboratory methods available for the diagnosis of malignant tumors are: Q. Histopathological specimens: Most commonly used fixative Histopathological Examination is 10% buffered formaline Histopathological diagnosis is based on the microscopic features of neoplasm and by this (formaldehyde). Morphological Methods method of examination, accurate diagnosis can be made in majority of cases. Examples:Radiation causes changes in the skin or mucosa mimic changes seen in cancer. Frozen Section In this method, tissue is frozen and sections are cut by special instrument called freezing microtome or cryostat. Its uses are: Rapid diagnosis: Frozen section is used for quick histologic diagnosis (within minutes) and useful for determining the nature of a tumor (benign or malignant) lesion, especially when the patient is still on the operation table. Evaluation of the margins of an excised cancer to know whether excision of the neoplasm is complete. Various Techniques for Tissue Sampling Needle biopsy: Using cutting needle, a core of tissue 1 to 2 mm wide and 2 cm long is obtained. Usually performed for lesions in gastrointestinal, respiratory, urinary and genital tracts. Incision biopsy: In this representative tissue sample is obtained by incising the lesions. Cytological Examination It is performed on many tissues and usually done for identifying neoplastic cells. Principle of exfoliative cytology: Cells normally exfoliate from any surface lining and this exfoliation increases in pathological conditions. Exfoliative cytology: It is the study of spontaneously exfoliated (shed) cells from the lining of an organ into a body cavity. Surface of mucosal or epithelial lining: Cells may be shed naturally or obtained by artificial exfoliation. The smears are prepared and stained, followed by microscopic examination of cells. Presently due to imaging techniques this method is also used to lesions in deep-seated structures. Method of Examination of Cytological Smears Liquid-based cytology (thin prep): this is a special technique for preparation of samples that provides uniform monolayered dispersion of cells on smears. Fixatives Used For Pap smears equal parts of ether and 95% ethanol or 95% ethanol alone Coating fixative as aerosol sprays or with dropper to the surface of a freshly prepared smears Pap smears are fixed immediately in fixative when smear is still wet and dry smears are fixed after the smear is air dried. Staining of Smears Cytological smears can be stained by: Papanicolaou stain is used for wet smears. Cytological Characteristics of Cancer Cells Cancer cells have decreased cohesiveness and show cellular features of anaplasia.

Inflammation and the accompanying repair process is a beneficial host response in most instances antibiotic iv 250 mg terramycin buy otc, but can sometimes be harmful antibiotic kidney infection terramycin 250 mg order line. Injury/damage to tissue and fibrosis Signs: Local and systemic Cardinal Signs of InflammationThe four cardinal signs of inflammation as mentioned by Celsus are listed in Table 2 virus compression purchase 250 mg terramycin overnight delivery. Celsus described the first 4 cardinal signs of inflammation namely: Rubor infection 9gag cheap 250 mg terramycin free shipping, calor antibiotic for strep throat discount 250 mg terramycin visa, tumor and dolor. Explain the sequential vascular changes/reactions of blood vessels/ hemodynamic changes in acute inflammation. Normal hydrostatic pressure in the capillary bed:About 32 mm Hg at the arterial end12 mm Hg at the venous end. Normal mean colloid osmotic pressure of tissues is about 25 mm Hg and is equal to the mean capillary hydrostatic pressure. Formation of exudate in inflammation Changes in Vascular Flow and Caliber Vasodilatation in acute inflammation isVasodilatation: It is the earliest feature of acute inflammation; sometimes it follows a responsible for the one transient constriction of arterioles. Increased Vascular Permeability (Vascular Leakage) Exudation: It is defined as the process of escape of fluid, proteins and circulating blood cells Increased vascular permeability: Hallmark of from the vessels into the interstitial tissue or body cavities. Escape of a protein-rich fluid causes edema and is one of the cardinal signs of inflammation. Mechanism of Increased Vascular Permeability Several mechanisms can cause increased vascular permeability: 1. Increased vascular permeability causes one of the cardinal signs of inflammation namely tumor (edema). Leukocyte-mediated vascular injury: the leukocyte (mainly neutrophils) which adheres to the endothelium during inflammation may themselves injure the endothelial cells. Increased transcytosis: Process of transport of fluids and proteins through the channels called vesiculovacuolar organelle is increased in number. Leakage from new blood vessels: During repair new blood vessels are formed (angiogenesis). Describe leukocyte/cellular events in acute inflammation Cellular events in acute inflammation:Leukocyte recruitmentLeukocyte activation. Leukocyte Recruitment/Extravasation Normally, leukocytes move rapidly in the blood, and during inflammation, they slow down and escape to the site of injury/causative agent in the extravascular space. Leukocyte extravasation is the process of migration of leukocytes from the lumen of the vessel to the site of injury in the extravascular tissues. Margination: When the blood flow slows down (stasis), leukocytes (mainly neutrophils) move towards the peripheral column and accumulate along on the endothelial surface of vessels. Describe the role of selectins and integrins in acute inflammation Pus: It is a purulent inflammatory exudate 1. The leukocytes first roll, and then firmly adhere to endothelium, followed by transmigration across the endothelium. Leukocytes pierce the basement membrane, and migrate toward chemoattractants from the source of injury. Rolling: Marginated leukocytes attach weakly to the endothelium, detach and bind again with a mild jumping movement. Selectins are either not present or expressed at low levels in unactivated endothelial cells. Adhesion of leukocyte to endothelium: Endothelium gets activated and leukocytes bind more firmly. Transmigration or diapedesis: Leukocytes migrate through the vessel wall by squeezing through the intercellular junctions between the endothelial cells. Migration across the basement membrane: Leukocytes penetrate the basement membrane of the vessel by secreting collagenases. Chemotaxis Definition: Chemotaxis is defined as process of migration of leukocytes toward the inflammatory stimulus in the direction of the gradient of locally produced chemoattractants. N-formylmethionine terminal amino acid)Endogenous:Cytokines, mainly chemokine family. Leukocyte recruited from blood into the extravascular tissue by a multi-step process. Define and write short note on chemotaxis Chemotaxis is the unidirectional movement of leukocytes towards injurious agent. Acute inflammation: Neutrophils predominate in early stage and are replaced by monocytes after 24 hours. Pseudomonas infection: Neutrophils predominate over 2 to 4 days Genetic deficiencies of leukocyte adhesion molecules cause recurrent bacterial infections. Recognition and attachment which involves binding to receptors on the leukocyte membrane to injurious agent. Engulfment, formation of phagosome and fusion of lysosomes with phagocytic vacuoles to form phagolysosome; C. Killing/degradation of ingested particles within the phagolysosomes by lysosomal enzymes and by reactive oxygen and nitrogen species Pinocytosis (cell drinking) and receptor mediated endocytosis: Requires clathrin coated pits. Characterized by increased susceptibility to infection, leukocytosis, and petechial hemorrhage due to impaired integrin activation. Leukocyte Activation Develops in two sequential events: Recognition of microbes, necrotic cells and foreign substances: Leukocytes recognize microbes, necrotic cells and foreign substances by cell surface receptors known as "pattern recognition receptors" the most important of these receptors are. Activation of leukocytes: Recognition of microbes or dead cells by the receptors initiates several responses in leukocytes together known as leukocyte activation. The most important functional responses of leukocyte activation is phagocytosis and intracellular killing. Phagocytosis Many leukocytes recognize, internalize, and digest foreign material, microorganisms, or cellular debris by a process termed phagocytosis. The major opsonins are IgG antibodies, the C3b breakdown product of complement, and certain plasma lectins called collectins Table 2. Opsonins include:AntibodiesComplement fragment C3bAcute phase proteins. Bruton disease: Defect in maturation of the B cells leading to absence of immunoglobulin production. Engulfment Next step in phagocytosis is engulfment and formation of a phagocytic vacuole. Clinical Significance of Defects in Phagolysosome Function Chiak-Higashi syndrome: Autosomal recessive condition characterized by:Increased susceptibility to infections: Due to defective fusion of phagosomes and lysosomes in phagocytes. Killing and Degradation Killing and degradation of ingested microbial agents/particles occurs within neutrophils and macrophages. Most important microbicidal agents are: 1) reactive oxygen species and 2) lysosomal enzymes. Clinical Significance of Inherited Defects in Microbicidal Activity Genetic or acquired defects in leukocyte function: Recurrent 1. These collections of activated macrophages try to wall off the microbes, forming aggregates called granulomas. General Features of Chemical MediatorsSource of mediators: Mediators are derived either from cells or from plasma proteins Table 2. Produced usually by platelets, neutrophils, monocytes/macrophages, and mast cells. They can act on one or few or many diverse targets, or may have different effects on different types of cells. Histamine and serotonin Source: Platelets, some neurons and enterochromaffin cells in the gastrointestinal tract). These are cyclooxygenase pathway (produce prostaglandins) and lipoxygenase pathway (produces leukotrienes and lipoxins). Arachidonic acid: Can be enzymatically converted into prostaglandins and leukotrienes (both together called as eicosanoids). Source: Many cells such as endothelial cells, macrophages and neurons in the brain. Cytokines and Chemokines these are polypeptides which function as mediators in immune responses and in inflammation (acute and chronic). Source: Cytokines are secreted by many types of cell (activated lymphocytes and macrophages, endothelial, epithelial, and connective tissue cells). Tumor Necrosis Factor and Interleukin-1 these are the two major cytokines involved in inflammation: Source: Activated macrophages. Stimuli: Endotoxin and other microbial products, immune complexes, physical injury, and many inflammatory stimuli. Chemokines Chemotactic cytokines or chemokines are small proteins, which selectively attracts various leukocytes to the site of inflammation. They activate leukocyte and promote their recruitment to the sites of inflammation. Smaller specific (or secondary) granules: They contain lysozyme, collagenase, gelatinase, lactoferrin, plasminogen activator, histaminase, and alkaline phosphatase. Larger azurophil (or primary) granules: They contain myeloperoxidase, bactericidal factors (lysozyme, defensins), acid hydrolases, and a variety of neutral proteases (elastase, cathepsin G, nonspecific collagenases, proteinase 3). Monocytes and Macrophages Lysosomal enzymes:Microbial killing They also contain acid hydrolases, collagenase, elastase, phospholipase, and plasminogenTissue injury activator. What are the three methods of complement activation and its effector function in acute inflammation Complement System associated with hereditary angioedema (edema at multiple sites including the larynx). The complement system is a group of plasma proteins synthesize in the liver, and are numbered C1 to C9. Lectin pathway: It directly activates C1 when plasma mannose-binding lectin binds to deficiency of C1 inhibitor is mannose on microbes. Leukocyte activation, adhesion and chemotaxis: C5a causes leukocyte activation, adhesion and C3a and C5a are powerful chemotactic agents for neutrophils, monocytes, eosinophils, and basophils. Opsonization and promote phagocytosis: C3b and its cleavage product iC3b (inactive C3b) act as opsonins and promote phagocytosis by neutrophils and macrophages through surface receptors for these complement fragments. IgM and IgG (IgM>IgG): Responsible for activation of classical complement pathway. Increased vascular permeability: C3a, C5a complement components stimulate histamine release from mast cells and thus increase vascular permeability and cause vasodilation. They are called anaphylatoxins, because their actions are similar to mast cell mediators involved in anaphylaxis. Interplay between innate and adaptive immune systemDefense against microbes through innate and adaptive immunity Other Functions:Clearance ofImmune complexes (Clq, C3)Apoptotic cells (Clq, C3). Activation of complement is controlled by cell-associated and circulating regulatory proteins. Fibrin split products: Plasmin degrades fibrin to form fibrin split products, which may increase vascular permeability. Activation of kallikrein produces kinins and activation of the coagulation system results in fibrin formation. Most important mediators involved in acute inflammation are summarized in Table 2. Write short note on role of different mediators in different reactions of inflammation. It occurs:When the injury is limited or short-livedWith no or minimal tissue damageWhen injured tissue is capable of regeneration. It occurs:When there is plenty of fibrin exudation in tissue or serous cavities (pleura, peritoneum) which cannot be removed or cleared. This process involves growing of connective tissue into the area of tissue damage or exudate, and is converted into a mass of fibrous tissue (scar). If the area of acute inflammation is walled off by inflammatory cells and fibrosis, neutrophil products destroy the tissue and form an abscess. Acute progress to chronic when the acute inflammatory response cannot be resolved. This may be due to:Persistence of the injurious agent orAbnormality in the process of healing. Examples: Bacterial infection of the lung may begin as acute inflammation (pneumonia). But when it fails to resolve, it can cause extensive tissue destruction and form a cavity with chronic inflammation known as lung abscess. Acute osteomyelitis if not treated properly may progress to chronic osteomyelitis. Chronic inflammation with a persisting stimulus results in peptic ulcer of the duodenum or stomach, which may persist for months or years. Write short note on morphological types/patterns of acute inflammatory reaction with suitable examples. Serous Inflammation of fluid in serous cavitiesCharacterized by marked outpouring of a thin serous fluid. Effusion: Accumulation Fibrinous InflammationMarked increase in vascular permeability leads to escape of large molecules like fibrinogen from the lumen of the vessel into the extravascular space and forms fibrin. When a fibrinous exudate develops on a serosal surface, such as the pleura or pericardium, it is known as fibrinous pleuritis or fibrinous pericarditis. Suppurative or Purulent Inflammation: AbscessIt is characterized by the production of large amounts of pus or purulent exudate. Abscesses have a central necrotic focus (consisting of necrotic leukocytes and necrotic parenchymal cells) surrounded by a zone of preserved neutrophils. Hemorrhagic InflammationWhen inflammation is associated with severe vascular injury or deficiency of coagulation factors, it causes hemorrhagic inflammation. Catarrhal InflammationAcute inflammation of a mucous membrane is accompanied by excessive secretion of mucus and the appearance is described as catarrhal. Michaelis Guttmann bodies are present in: Malacoplakia Membranous InflammationIn this type, epithelium is covered by membrane consisting of fibrin, desquamated epithelial cells and inflammatory cells. Pseudomembranous InflammationSuperficial mucosal ulceration covered by sloughed mucosa, fibrin, mucus and inflammatory cells. Ulcer An ulcer is defined as a local defect, or excavation, of the surface of an organ or tissue.

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• Valacyclovir

References

• Spiegel R, Raas-Rothschild A, Reish O, et al. The clinical spectrum of fetal Niemann-Pick type C. Am J Med Genet A 2009;149A:446.
• Bossuyt PM, Reitsma JB, Bruns DE et al. Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative. Standards for Reporting of Diagnostic Accuracy. BMJ 2003; 326: 41-4. 12.
• Gottlieb LM, Handelsman JC. Treatment of outflow tract problems associated with continent ileostomy (Kock pouch). Report of six cases. Dis Colon Rectum 1991;34:936-40.
• Shaver JA. Cardiac auscultation: a cost-effective diagnostic skill. Curr Probl Cardiol. 1995;20:441-532.
• GUPTA R et al: Genital herpes. Lancet 370:2127, 2007.