Deck III Flashcards Preview

USMLE World Missed Questions > Deck III > Flashcards

Flashcards in Deck III Deck (30):
1

Maternal blood types A and B antibodies are of what immunoglobulin class?

IgM.

2

Maternal blood type O antibodies are of what immunoglobulin class?

IgG.

3

Where do B cells aggregate in lymph nodes?

In germinal centres.

4

Where do T cells and dendritic cells primarily aggregate in lymph nodes?

In the paracortex.

5

What types of bacteria contain polysaccharide capsules which can be covalently bound to protein carriers and used as vaccine antigens?

Encapsulated bacteria.

6

Name four approved protein carriers that are used as vaccine antigens.

Mutant nontoxic diptheria toxin, Neisseria meningitidis outer membrane protein complex, and tetanus toxoid.

7

What is the pathophysiology associated with polymyositis?

Damage to myocytes with overexpression of MHC Class I proteins on the sarcolemma leads to infiltration with CD8+ T lymphocytes and myocyte damage.

8

Which cytokines preferentially promote B cell IgE production?

IL-4 and IL-13.

9

Which cytokine promotes eosinophil production?

IL-5.

10

Where do T-lymphocytes undergo positive selection?

Thymic cortex.

11

Where do T-lymphocytes undergo negative selection?

Thymic medulla

12

Describe the process of transmigration in inflammatory leukocyte accumulation.

Neutrophils migrate out of the vasculature by squeezing in between the cells via integrin attachments and adherence to platelet endothelial cell adhesion molecule I (PECAM-1) which is a protein found primarily at the peripheral intercellular junctions of endothelial cells.

13

What cell types are primarily responsible for clonal proliferation/ response to the EBV virus?

CD8+ lymphocytes.

14

Describe a CD8+ lymphocyte as seen on peripheral blood smear.

Cells much larger than quiescent lymphocytes with abundant cytoplasm, an eccentrically placed nucleus and a cell membrane that appears to conform to the borders of neighbouring cells.

15

Name the four seronegative spondyloarthropathies.

Ankylosing spondylosis, psoriatic arthritis, arthritis associated with IBD, and reactive arthritis.

16

What is the most important virulence factor expressed by uropathogenic E. Coli?

P fimbriae.

17

What contributes to host defense against Candida infection?

T-lymphocytes and neutrophils; T-lymphocytes prevent spread of superficial infection; neutrophils prevent hematogenous spread.

18

What histopathology is most consistent with acute heart rejection?

Acute cardiac rejection is a cell-mediated process. It consistes of a dense infiltrate of mononuclear cells, usually composed primarily of T-lymphocytes.

19

How do interferons mediate damage to virally infected cells?

By decreasing protein synthesis by infected cells. mRNA of both viral and host cells is degraded.

20

How does high dose IL-2 significantly reduce tumor burden in renal cell carcinoma and metastatic melanoma?

By enhanced activity of NK cells.

21

What is the function of IL-2?

To promote growth of B cells, to activate NK cells, to activate myocytes, to stimulate the growth, differentiation, and survival of antigen specific CD4+ T cells and CD8+ T cells.

22

What causes jejunal, ileal, and duodeonal atresia?

Vascular accidents in utero- diminished perfusion leads to ischemia and narrowing; NOT caused by congenital malformations

23

What area of the bowel is most often affected by vascular ischemia in utero?

The ileum.

24

What occurs as a result of superior mesenteric ischemia in utero?

Apple peel atresia ending in a blind ending proximal jejunum with absence of the long length of the small bowel and dorsal mesentary. The terminal ileum distal to the atresia assumes a spiral configuration around an ileocolic vessel.

25

What artery may be perforated by an ulcer of the posterior duodenal wall?

Gastroduodenal artery

26

Hydrocele (e.g. scrotal enlargement) is formed by a similar mechanism?

Indirect inguinal hernia (formed by an anatomical communication)

27

The IVC is formed by the union of what veins?

Formed by the union of the common illiac veins.

28

At what vertebral level do the renal arteries lie?

L1.

29

What are the two most common causes of eugonadotropic amenorrhea?

Incomplete canallization of the vaginal plate or mullerian duct anomalies

30

When is eugonadotropic amenorrhea a likely diagnosis?

In conditions where the patient has fully developed secondary sexual characteristics (i.e. normal levels of estrogens and gonadotropins)