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15 Cards in this Set

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How long do macrophages last?
They last for many years. T and B memory cells last the life of an individual.
A previously healthy 45 yr old woman is admitted to the hospital b/c of lower GI bleeding for 3 days. She has a PCV of 25%. Her blood type is O, Rh+. Three units of blood are administered over a 3 day period. During administration of a 4th unit, she develops shortness of breath and severe back pain. her temperature is elevated, and is hypotensive, and has reddish brown urine. What is the most likely cause?
The patient exhibits the classic signs of an ABO transfusion reaction. She had an immediate and massive immune response resulting in the destruction of RBC, release of hemoglobin in the urine. Bacterial complications take place over time.
Eosinophils constitute about 2 % of the total WBC count, but they are produced in large numbers in people with parasitic infections. TRUE/FALSE
TRUE.
Interleukin-2(IL-2) is an important molecule in the immune response. What is its function?
It stimulates proliferation of cytotoxic T cells. It is secreted by helper T cells when the T cells are activated by specific antigens. IL-2 plays a specific role in the growth and proliferation of both cytotoxic and suppressor T cells, and activation of helper T cells.
What is the normal platelet count?
The normal platelet count is between 150,000-400,000. The bleeding time is used to test platelet function, and a normal value is between 2 and 7 minutes.
What are the three major pathogenic species of staphylococcus?
Staphylococcus aureus
Staph. epidermidis
Staph. saprophyticus.
Most Staph are penicillin G resistant. Three tests are employed to differentiate them. Gram stain/Catalase test/Culture.
How do Staph. species react in Gram stain?
They lie in grape like clusters. It is catalase positive. Staph aureus can be differentiated from the other beta hemolytic cocci by their elaboration of a golden pigment when cultured on sheep blood agar.
All staphylococci have the enzyme catalase, and streptococci do not. True/False
True
What is a simple method of catalase testing regarding staphylococci?
To test, rub a wire loop across a colony of Gram+ cocci and mix on a slide with H2O2. If bubbles appear, this indicates that H2O2 is being broken down into O2 bubbles and water; catalase positive staphylococci are present.
How can Staph. aureus be differentiated from other beta hemolytic cocci?
By their elaboration of a golden pigment on sheep blood agar.
Only Staph. aureus is coagulase positive. TRUE/FALSE
TRUE. It elaborates the enzyme, coagulase, which activates prothrombin, causing blood to clot. When a G+ coccus in clusters is isolated in culture, the laboratory will do a coagulase test. If the test demonstartes coagulase positive G+ cocci in clusters you know you have Staph. aureus. If they report coagulase neg G+ cocci in clusters, think of Staph. epidermidis or Staph saprophyticus.
Does Staph. aureus possess a microcapsule?
Yes. It surrounds its huge peptidoglcan cell wall, which in turn surrounds a cell membrane containing penicillin binding protein(transpeptidase)
List 5 bacterial proteins that can disable our immune defenses.
1. Protein A- This protein has sites that bind the Fc portion of IgG. may protect from opsonization and phagocytosis.
2. Coagulase-can lead to fibrin formation around bacteria, protecting from phagocytosis.
3. Hemolysans(4 types), Alpha, beta, gamma and delta. They destroy RBC, and neutrophils.
4.Leukocidans- Destroy WBCs.
5. Penicillinase- This is a secreted form of beta-lactamase. It dirupts the beta lactam ring of the penicillin molecule.
6. Novel penicillin binding protein.Some strains of Staph aureus have new penicillin binding proteins that are resistant to penicillinase resistant penicillins and cephalosporins.
List 3 proteins produced by Staph. aureus that permit the tunneling of tissue.
1. Hyaluronidase- breaks down proteoglycans in connective tissue.
2.Staphylokinase-lyses formed fibrin.
3. Lipase-degrades fats and oils.
List three exotoxins.
1. Exfoliatin
2. Enterotoxins
3. Toxic shock syndrome.(TSST-1)
Exfoliatin-causes the skin to slough(scalded skin syndrome)
Enterotoxins-cause food poisoning.