Rx_1.1

Question 1

How to calculate drug clearance

Answer 1

clearance = rate of drug elimination/plasma drug concentration

Question 2

Common pulmonary infection in HIV patient

Answer 2

• Pneumocystis jiroveci ==> interstitial pneumonia

Question 3

Fxn + name of HIV surface proteins

Answer 3

• two imporant envelope proteins:
  
  • gp41
  • gp120
• fxn of surface proteins is to bind CD4 receptors ==> envelope fusion and HIV entru into cell

Question 4

Stage of cell cycle of oocyte from birth to ovulation

Answer 4

prophase I

Question 5

Oocyte cell cycle from ovulation ==> embryo

Answer 5

• at birth: all oocytes arrested in meiosis I (prophase I)
• after ovulation: oocye progresses through miosis I ==> metaphase II
• oocyte is arrested in metaphase II until fertilization
• after fertilization: oocyte completes meiosis II and begins mitotic growth of embryo

Question 6

Lead impact on heme synthesis

Answer 6

• Lead inhibitions ALA dehydratase and ferrochelatase
  
  • ALA dehydratase mediates conversion of ALA to porphobilinogen
  • ferrochelatase incorporates iron into protoporphyrin IX (final step in heme synthesis)

Question 7

Tx w/penicillins, sulfonamides followed by fatigue, temp + erythematous macules/papules + burning sensation ==> Dx?

Answer 7

• Stevens-Johnson syndrome (acute epidermal disorder)
• urticaria-erythema multiforme-toxic epidermal necrolysis

Question 8

Drugs that ==> Stevens-Johnson syndrome

Answer 8

• penicillins
• sulfonamides
• ethosuximide (anticonvulsant: absence/epileptic seizures)
• lamotrigine (anti-epileptic; mood stabilizer)

Question 9

Dx?

Answer 9

• interstitial pneumonia
• most likely p. jiroveci

Question 10

Tx of Pneumocystitis jiroveci pneumonia (+ MOA)

Answer 10

• trimethoprim-sulfamethoxazole
  
  • MOA = inhibitis bacterial folate synthesis via inhibition:
  • dihydropteroate synthetase (trimetho) and dihydrofolate reductase (sulfa)

Question 11

Characteristics of H. pylori

Answer 11

• gram -
• flagellated
• oxidase +
• helical organism
• produces urease
• most common cause of gastric ulcers
  
  • classic = antral ulcer with regular, rounded edges and smooth base

Question 12

p53 gene fxn

Answer 12

• p53 = tumor suppressor gene
• activated by DNA damage due to chemical insult, oxidate stress, UV radiation ==>
  
  • arrest of cell cycle progression
  • DNA repair
  • apoptosis

Question 13

location of p53 gene

Answer 13

chromosome 17

Question 14

Consequences of loss of p53 gene

Answer 14

• neoplasm:
  
  • lung
  • breast
  • colon
• Li-Fraumeni syndrome

Question 15

diagnostic criteria for Li-Fraumeni syndrome

Answer 15

1. age < 45 yrs
2. first-degree relative w/cancer @ <45 yrs
3. another first or second-degree relative w/cancer @ <45 yrs or sarcoma at any age

Question 16

Celiac artery supplies blood to ….?

Answer 16

• celiac ==> L gastric, splenic, common
• foregut structures
  
  • stomach
  • proximal duodenum
  • liver
  • gallbladder
  • pancreas
• spleen

Question 17

fever + runny nose + bilateral cervical lymph nodes ==> Dx?

Answer 17

Corynebacterium diptheria infection

Question 18

MOA of diptheria toxin

Answer 18

• adenosine diphosphate ribosylation of elongation factor 2 ==>
• inhibtion of protein syntehsis in animal cells ==> cell death

Question 19

Consequence of 21-alpha-hydroxylase deficiency

Answer 19

unable to synthesize mineralocorticoids ==> chronically elevated renin levels

Question 20

Pathophysiology of osteogenesis imperfect

Answer 20

• defect in type 1 collagen
• type 1 collagen production is decreased due to inability of pro-alpha chain mRNA to be translated into polypeptides

Question 21

Mutations in Type 1 osteogenesis imperfecta

Answer 21

• COL1A1 or COL1A2 (encorde alpha1 and alpha2 collagen chains)
• ==> inability of mRNA to be translated

Question 22

Pathologic finding?

Answer 22

• Heinz bodies = hemoglobin inclusions w/in red blood cell
• common in hemolytic anemia

Question 23

Presentation of G6PD

Answer 23

• previously health patient
  
  • common in people of African or Mediterranean origin
• development of hemolytic anemia after treatment for bacterial infection