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* NBME 7 Block 1___________plz help
 #502270  
  iqbalian01 - 04/26/10 20:00
 
  4) A stillborn male newborn is delivered to a 32 yr old primigravida woman at 36 week’s gestation. A photograph of newborn is shown. Histologic exam of sacrococcygeal tumor shows a haphazard arrangement of somatic tissues representing derivatives of ectoderm, mesoderm, & endoderm. The pathogenesis of this congenital neoplasm is most likely related to a defect arising during which of the following developmental processes?

A) head mesenchymal proliferation
b) hematopoiesis
c) neural crest formation
d) neural tube closure
e) primordial germ cell migration
f) somite development


7) A 9 month old girl is brought to ER 30mins after she had generalized tonic-clonic seizures. She has had failure to thrive & developmental delay since birth. She is at the 3rd percentile for length & weight. Physical exam shows microcephaly, tachypnea, & hypotonia. Lab studies show hypoglycemia, hyperalaninemia, & lactic acidosis. After I/V glucose is administered, her serum glucose concentration returns to within the reference range. This patient most likely has a deficiency of which of the following enzyme activities?

a) glucokinase
b) glyceraldehydes-3-phosphate dehydrogenase
c) hexokinase
d) pyruvate carboxylase
e) triose-phosphate isomerase

22 ) what is in the x-ray showing…please describe.


25) a healthy 54 year old woman undergoes an exercise stress test. During the moderate phase of the exercise, her pulse is 140/min, respirations are 25/min, & bp is 130/90 mmHg. Which of the following is the relative proportion of coronary oxygen delivery during the rest & during the exercise times?

Rest moderate exercise
a) systolic > diastolic systolic > diastolic
b) systolic > diastolic systolic < dia
c) systolic < diastolic systolic > diastolic
d) sys < dia sys < dia
e) sys = dia sys > dia
f) sys = diastolic sys < dia


27) a 9 year old girl has had polyuria, polydipsia, & weight loss for the past 3 weeks. She is alert, her breath has a fruity odor, & she has tachypnea. Lab studies show:

Serum:
Na+ : 130 mEq/L
Cl- : 100 mEq/L
K+ : 5.8 mEq/L
HCO3- : 6.0 mEq/L
Glucose 700 mg/dL

Arterial blood gases:
pH 7.0
Pco2 : 16 mmHg

Which of the following sets of additional findings in serum is most likely?

Beta-hydroxybutryate osmolarity anion gap
a) decrease decrease increase
b) decrease increase decrease
c) increase decrease increase
d) increase increase decrease
e) increase increase increase



41) a 25 year old woman comes to the physician because of increasingly severe pain of the right hip during the past week. She runs 5 miles daily & recently changed her route because of construction. She now runs on uneven ground rather than pavement. Range of motion of the hip is full. The pain is exacerbated by flexion & internal rotation of the hip & by direct palpation over the lateral aspect of the hip. Which of the following structures is most likely involved in her condition?

a) anserine bursa
b) ischial bursa
c) psoas bursa
d) sacroiliac joint
e) sciatic nerve
f) trochanteric bursa


45) a 29 year old woman comes to the physician because of a 1 week history of nausea, and vomiting in the mornings. Her last menstrual period was 8 weeks ago. Current medications include an oral contraceptive; she has not missed any doses during the past 2 years. Four months ago, she began taking an herbal preparation that was given to her by a friend, but she cannot remember the name of the herb. Physical exam shows a uterus consistent in size with an 8 week gestation. A urine pregnancy test result is positive. This patient has most likely been taking which of the following herbal preparations?

a) Echinacea
b) ginkgo biloba
c) ginseng
d) saw palmetto
e) st. john’s wort

47) a 42 year old man needs a kidney allograft. His lymphocytes are examined by the mixed lymphocyte reaction with killed stimulator cells from himself & from each of 5 prospective donors. A donor with which of the following thymidine incorporation (cpm) will be most compatible? (the patient has a thymidine value of 425/cpm)

a) 312
b) 1542
c) 2505
d) 15,389
e) 27,482


49) a 72 year old woman comes to the physician because of an 8-month history of burning chest pain & a bitter taste in her mouth; both symptoms occur at night when she lies down. The pain does not radiate & is not associated with shortness of breath. Physical examination shows no abnormalities. Which of the following is most likely to be associated with her symptoms?

a) atrophic gastritis
b) H.pylori infection
c) impaired relaxation of the lower esophageal sphincter
d) metaplasia of the esophageal epithelium
e) spasm of the esophageal smooth muscle



please provide explanations with your answers. thanks!!!
 
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* Re:NBME 7 Block 1___________plz help
#2090607
  jollyy - 04/26/10 20:30
 
  4: E S teratoma is derivative of primitive streak which involves process of germ cell migration..
7: D? not sure
25: D?
27: E
41: F
45: E
49: C?
 
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* Re:NBME 7 Block 1___________plz help
#2090628
  yeabiruh - 04/26/10 20:55
 
  for number 25 .....the cardiac cycle where by coronary arteries deliver oxygen to the myocardium is during diastole........whether it is systolic or diastolic.....this is my assumption...dddd  
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* Re:NBME 7 Block 1___________plz help
#2090641
  yeabiruh - 04/26/10 21:09
 
  27...case of diabetic ketoacidosis...high glucose ...high ketones

Betahydroxy butyrate and acetoacetate both increase.....

Osmolarity =2 Serum Na+serum glucose /18+BUN/2.8 ...so if u increase glucose u increase

plasma osmolarity

Anion Gap =Serum Na-(serum Chloride+Serum HCO3)...in the case of diabetic Ketoacidosis

anions of acid (acetoacetate and beta hydroxybutyrate) replace HCO3 ...hence we only subtract Chloride from the Serum Na ...that makes the anion gap to increase....

my answer EEEEE
 
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* Re:NBME 7 Block 1___________plz help
#2090646
  yeabiruh - 04/26/10 21:17
 
  45....her OCP are metabolized faster ....which predisposes her to pregnancy....and St John's

wort has been shown to cause multiple drug interactions through induction of the cytochrome

P450 enzyme CYP3A4, but also CYP2C9. This results in the increased metabolism of those

drugs, resulting in decreased concentration and clinical effect. The principal constituent

thought to be responsible is hyperforin.


my answer E
 
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* Re:NBME 7 Block 1___________plz help
#2090658
  yeabiruh - 04/26/10 21:32
 
  CPM ...stands for count per minute ..which is a measure of radioactivity. It is the number of

atoms in a given quantity of radioactive material that are detected to have decayed in one

minute.

Mixed Lymphocyte Reaction... a test used to check class II compatibilty testing ...in this test

lymphocytes from one individual being tested(donor ) are irradiated so that they cant proliferate..

but will act as a stimulator cells for the presentation of MHC antigens ...the other individual

cells (Recipient) are added to the culture ,and uptake of tritiated thymidine is used as an

indicator of cell proliferation....if the MHC class II antigens are different ,proliferation will

occur ..if they are the same, no proliferation will occurr.....

Proliferation is directly proportional to CPM

high CPM .....high proliferation....MHC II different ...not compatible

low CPM ...less proliferation...MHC II similar...less risk of rejection....compatible

mY ANSWER AAAA
 
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* Re:NBME 7 Block 1___________plz help
#2090662
  yeabiruh - 04/26/10 21:36
 
  41 ...F here is the link

http://emedicine.medscape.com/article/309286-overview
 
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* Re:NBME 7 Block 1___________plz help
#2090680
  iqbalian01 - 04/26/10 21:58
 
  thanks jollyy. thanks a lot yeabiruh!!

for Q25) i think you are right and i believe that no matter if the person is at rest or doing exercise, the coronary blood flow is always more during diastole. although the duration of flow is greatest during rest as oppose to exercise when the heart rate is faster and thus diastole is of less duration. please correct me if i'm wrong with the explanation.

Q27) i chose 'c' originally because i though that beta-hydroxybutyrate and anion gap were increased and the osmolarity is decreased because of the decreased sodium (there is dilutional hyponatremia as a result of glucose overriding sodium). but i guess glucose would be the one causing the increased osmolarity. is the later statement correct???

Q45) oh wow, i never came across a question about st.john's wort. i memorized it was an inducer of cytochrome P450. but now when i had to apply it here, it didnt click. thanks so much, great explanations!!!

 
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* Re:NBME 7 Block 1___________plz help
#2090699
  yeabiruh - 04/26/10 22:35
 
  For number 4...This is a case of Sacrococcygeal teratoma...(by the way I dont have NBME 7

and I am not able to see the pictures)....

Sacrococcygeal teratoma is one of the extragonadal germ cell tumors ...This is what I get

from emedicine.......These tumors can be found anywhere on the midline, particularly the

retroperitoneum, the anterior mediastinum, the sacrococcyx, and the pineal gland. Other

less common sites include the orbit, suprasellar area, palate, thyroid, submandibular region,

anterior abdominal wall, stomach, liver, vagina, and prostate. The classic theory suggests

that germ cell tumors (GCTs) in these areas are derived from local transformation of

primordial germ cells misplaced during embryogenesis...which means defect in primordial

germ cell migration ......here is the link

http://emedicine.medscape.com/article/278174-overview.....

My answer Is EE

F ... is for sacral agenesis

D..is for spina bifida

C..is for neurocristopathies, which include conditions such as frontonasal dysplasia,

Waardenburg-Shah syndrome, and DiGeorge syndrome, ......etc

B..is clear

A...is for cranial abnormalities.....
 
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* Re:NBME 7 Block 1___________plz help
#2090707
  yeabiruh - 04/26/10 22:50
 
  Number 49...This is a case of GERD...with esophagitis for the last 8 months...

Gastroesophageal reflux disease (GERD) occurs when the amount of gastric juice that

refluxes into the esophagus exceeds the normal limit, causing symptoms with or without

associated esophageal mucosal injury (ie, esophagitis).

Pathogenesis of GERD...Transient relaxation of LES and Ineffective esophageal clearance of

reflux material (bile acid and gastric juice)...hence the amount of acid that is secreted by the

stomach doesnt have any significant effect ...also whether there is H pylori or not has no

significance ...as well as whether the stomac is atrophic or not ...

Hence I go for metaplasia of the esophageal epithelium (given the 8 month history ) ...
 
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* Re:NBME 7 Block 1___________plz help
#2090716
  suhanosh - 04/26/10 23:08
 
  Hi qbalian,
The Q you posted i didnt I wasnt sure about the answer but thanks to every body here.
Do you have Answers for the NBME 7--- last 3 blocks please?
 
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