NBME Step 1 (Answered) Verified
Solution
Formation of hypnozoites
-Pt has malaria → one of the features is that it forms hypnozoites and has the
PBS shown
Chloroquine resistance
-Can happen but it is not a feature
A 30M, who is a migrant farm worker presents to the ED b/c of a 1-wk Hx of fever, chills,
& severe headache. He immigrated to the midwestern USA from Honduras 1 year ago.
He is alert. Temp is 104F, pulse is 101/min, RR are 20/min, BP is 105/62. The lungs are
clear to auscultation. Cardiac exam is normal. The abd is soft w/active bowel sounds.
Neuro exam shows a supple neck; there is nu nuchal rigidity. He is oriented to person,
place, & time. Labs show:
-Hb---------------14
-Hct---------------42%
-Leuko's----------4,6K
-Neutro's----------57%
-Lymph's-----------33%
-Monocytes-------10%
Urine
-Color------clear yellow
-Blood-------------1+
-Urobilinogen-----trace
A pictomicrograph of a PBS is shown. This pt's overall condition is most likely caused by
an infectious agent w/which of the following features?
(Formation of hypnozoites
OR
Chloroquine resistance)
Conjugation
-Allows for transfer of DNA high frequency transfer via:
1-direct cell-to-cell contact
2-via a bridge-like connection pilus between two cells
-Classically E.coli allows antibiotic resistance transfer to another species
Transduction
-Transfer of genetic material via a bacterial phage → Lytic page infects a
bacterium, leading to cleavage of bacterial DNA → Parts of bacterial
chromosomal DNA then b/c packaged in capsid → phage infects another bacteria
In a study of antibiotic resistance, a strain of E.coli resistant to ampicillin but sensitive to
streptomycin is cultured w/a strain of salmonella enteritidis sensitive to ampicillin but
resistant to streptomycin. After 4 hrs of co-cultivation. the broth is plated onto a solid
,medium containing both ampicillin & streptomycin. S.enteritidis bacteria that are
resistant to both antibiotics grow at a frequency rate of 1 per 100 cells.
Which of the following is the most likely mechanism of the acquisition of ampicillin
resistance by S.enteritidis?
(Conjugation
OR
Transduction)
20
-Vd is calculated two ways
1-t1/2 = (0.7xVd)/CL
OR
VD=(C-initial)/Plasma conc
We use the second eq so
VD = 80mg/(4ug/mL)
-but we must convert 4ug to mg so
Vd = 80mg/(.004mg/mL) =
20,000mL
-then convert to Liters
20,000mL/(1L/1000mL) =
20L
An 80M is admitted to the hospital b/c of a 2 wks Hx of severe, persistent UTI. An 80-
mg dose of Drug X is administered IV. Thirty mins after the infusion is complete, his
serum conc of Drug X is 4ug/mL.
Assuming a distribution t1/2 life of 3 mins & an elimination t1/2 of 24 hrs, the volume of
distribution of this drug (in L) in the peripheral compartment is closest to which of the
following?
(2
OR
20)
Negative strand RNA
Also:PaRaMMyxovirus
1-Mumps & Measles
2-Parainfluenza
3-RSV
Is Rubeola (measles) virus a
(Negative strand RNA
OR
Postive strand RNA)
Regular exercise
-Prevents disease in healthy people → other primary preventions are:
1-Legislation to ban use of hazardous products (asbestos) or to mandate safe
practices (seat belts, helmets)
,2-Education about health & safe habits (eating well, exercise, not smoking)
3-Immunization
Annual mammography
-This is used to detect breast cancer only detects after it has already occurred →
so secondary prevention → other examples include
1-Daily, low-dose aspirin OR diet and exercise programs after a stroke to prevent
future strokes)
2-Modified work so injured of ill workers can return safely to job
Tertiary
1-Cardiac or stroke rehab programs, chronic disease mgmt programs (DM,
arthritis, depression)
2-Support groups
3-Vocational rehab programs to retrain workers
A public health consultant is contacted by a HMO for recommendations about a primary
health prevention techniques for a population of women ages 30-40 years.
Which of the following is most appropriate primary preventative recommendation for this
group?
(Regular exercise
OR
Annual mammography)
TGF-β
-Wound healing
-Stimulates angiogenesis & fibrosis (fibroblast migration & proliferation) -
resolution of the inflammatory response
TNF-α
-Causes cachexia in malignancy
-Maintains granulomas
-Activates endothelium, causes WBC recruitment, vascular leak
A pt presents w/a subcutaneous nodule. Micro exam of the nodule shows fibrous CT,
M∅, multinucleated giant cells, fibroblasts, a few lymphocytes, & scattered fragments of
polarizable foreign material.
Which of the following substances that promotes fibroblast migration & proliferation
most likely led to this lesion?
(TGF-β
OR
TNF-α)
The pt has another mutation that was not included in the previous analysis
-For a pt to exhibit symptoms in CF they must have two dysfunctional alleles,
which must be on the same gene
The pt has a mutation in another gene for a protein that interacts w/ CFTR
, -CF is a AR disorder so two non-functional mutations are needed to see
symptoms
-If the pt has a mutation in a different gene she would not have symptoms
A 3-week-old F newborn, presents for a follow-up exam after the results of a newborn
screening showed an increase serum conc of immunoreactive trypsin. CF is suspected.
At 4-months, her sweat chloride conc is >60mmol/L (N<40). Molecular analysis that
includes a panel pf the 70 most common CF transmembrane gene mutations is done.
Results shows a mutation in one allele.
Which of the following best explains the findings in this pt?
(The pt has another mutation that was not included in the previous analysis
OR
The pt has a mutation in another gene for a protein that interacts w/ CFTR)
G2
-DNA synthesis & mitosis
G1
-Cells increase in size & get ready for DNA replication
-Retinoblastoma & osteosarcoma affect here
S
-DNA replication occurs
In which of the following stages of the cell cycle are mitotic cyclins synthesized?
(S
OR
G2
OR
G1)
Granulation tissue
-Pic shows granulation tissue
-Also, 18 days after MI we would expect to see granulation tissue not granulomas
A 52M, is admitted to the hospital for tmt of a massive acute MI. Tmt w/O2, β-blockers,
aspirin, & reperfusion therapy is initiated. 18 days later, he develops v-fib, from which he
cannot be resuscitated. A photomicrograph of cardiac tissue from the site of infarct
obtained at autopsy is shown.
Which of the following best describes the appearance of this pt's heart?
(Granulation tissue
OR
Granuloma)
1 in 4 will have 25% β-globin function & may require occasional transfusions
-Use punnet square, works out to 1 in 4 will be affected
-Father → A A(not functional)
-Mom → A a(affected)
-Heme holds 4 so all expect one would be affected
Solution
Formation of hypnozoites
-Pt has malaria → one of the features is that it forms hypnozoites and has the
PBS shown
Chloroquine resistance
-Can happen but it is not a feature
A 30M, who is a migrant farm worker presents to the ED b/c of a 1-wk Hx of fever, chills,
& severe headache. He immigrated to the midwestern USA from Honduras 1 year ago.
He is alert. Temp is 104F, pulse is 101/min, RR are 20/min, BP is 105/62. The lungs are
clear to auscultation. Cardiac exam is normal. The abd is soft w/active bowel sounds.
Neuro exam shows a supple neck; there is nu nuchal rigidity. He is oriented to person,
place, & time. Labs show:
-Hb---------------14
-Hct---------------42%
-Leuko's----------4,6K
-Neutro's----------57%
-Lymph's-----------33%
-Monocytes-------10%
Urine
-Color------clear yellow
-Blood-------------1+
-Urobilinogen-----trace
A pictomicrograph of a PBS is shown. This pt's overall condition is most likely caused by
an infectious agent w/which of the following features?
(Formation of hypnozoites
OR
Chloroquine resistance)
Conjugation
-Allows for transfer of DNA high frequency transfer via:
1-direct cell-to-cell contact
2-via a bridge-like connection pilus between two cells
-Classically E.coli allows antibiotic resistance transfer to another species
Transduction
-Transfer of genetic material via a bacterial phage → Lytic page infects a
bacterium, leading to cleavage of bacterial DNA → Parts of bacterial
chromosomal DNA then b/c packaged in capsid → phage infects another bacteria
In a study of antibiotic resistance, a strain of E.coli resistant to ampicillin but sensitive to
streptomycin is cultured w/a strain of salmonella enteritidis sensitive to ampicillin but
resistant to streptomycin. After 4 hrs of co-cultivation. the broth is plated onto a solid
,medium containing both ampicillin & streptomycin. S.enteritidis bacteria that are
resistant to both antibiotics grow at a frequency rate of 1 per 100 cells.
Which of the following is the most likely mechanism of the acquisition of ampicillin
resistance by S.enteritidis?
(Conjugation
OR
Transduction)
20
-Vd is calculated two ways
1-t1/2 = (0.7xVd)/CL
OR
VD=(C-initial)/Plasma conc
We use the second eq so
VD = 80mg/(4ug/mL)
-but we must convert 4ug to mg so
Vd = 80mg/(.004mg/mL) =
20,000mL
-then convert to Liters
20,000mL/(1L/1000mL) =
20L
An 80M is admitted to the hospital b/c of a 2 wks Hx of severe, persistent UTI. An 80-
mg dose of Drug X is administered IV. Thirty mins after the infusion is complete, his
serum conc of Drug X is 4ug/mL.
Assuming a distribution t1/2 life of 3 mins & an elimination t1/2 of 24 hrs, the volume of
distribution of this drug (in L) in the peripheral compartment is closest to which of the
following?
(2
OR
20)
Negative strand RNA
Also:PaRaMMyxovirus
1-Mumps & Measles
2-Parainfluenza
3-RSV
Is Rubeola (measles) virus a
(Negative strand RNA
OR
Postive strand RNA)
Regular exercise
-Prevents disease in healthy people → other primary preventions are:
1-Legislation to ban use of hazardous products (asbestos) or to mandate safe
practices (seat belts, helmets)
,2-Education about health & safe habits (eating well, exercise, not smoking)
3-Immunization
Annual mammography
-This is used to detect breast cancer only detects after it has already occurred →
so secondary prevention → other examples include
1-Daily, low-dose aspirin OR diet and exercise programs after a stroke to prevent
future strokes)
2-Modified work so injured of ill workers can return safely to job
Tertiary
1-Cardiac or stroke rehab programs, chronic disease mgmt programs (DM,
arthritis, depression)
2-Support groups
3-Vocational rehab programs to retrain workers
A public health consultant is contacted by a HMO for recommendations about a primary
health prevention techniques for a population of women ages 30-40 years.
Which of the following is most appropriate primary preventative recommendation for this
group?
(Regular exercise
OR
Annual mammography)
TGF-β
-Wound healing
-Stimulates angiogenesis & fibrosis (fibroblast migration & proliferation) -
resolution of the inflammatory response
TNF-α
-Causes cachexia in malignancy
-Maintains granulomas
-Activates endothelium, causes WBC recruitment, vascular leak
A pt presents w/a subcutaneous nodule. Micro exam of the nodule shows fibrous CT,
M∅, multinucleated giant cells, fibroblasts, a few lymphocytes, & scattered fragments of
polarizable foreign material.
Which of the following substances that promotes fibroblast migration & proliferation
most likely led to this lesion?
(TGF-β
OR
TNF-α)
The pt has another mutation that was not included in the previous analysis
-For a pt to exhibit symptoms in CF they must have two dysfunctional alleles,
which must be on the same gene
The pt has a mutation in another gene for a protein that interacts w/ CFTR
, -CF is a AR disorder so two non-functional mutations are needed to see
symptoms
-If the pt has a mutation in a different gene she would not have symptoms
A 3-week-old F newborn, presents for a follow-up exam after the results of a newborn
screening showed an increase serum conc of immunoreactive trypsin. CF is suspected.
At 4-months, her sweat chloride conc is >60mmol/L (N<40). Molecular analysis that
includes a panel pf the 70 most common CF transmembrane gene mutations is done.
Results shows a mutation in one allele.
Which of the following best explains the findings in this pt?
(The pt has another mutation that was not included in the previous analysis
OR
The pt has a mutation in another gene for a protein that interacts w/ CFTR)
G2
-DNA synthesis & mitosis
G1
-Cells increase in size & get ready for DNA replication
-Retinoblastoma & osteosarcoma affect here
S
-DNA replication occurs
In which of the following stages of the cell cycle are mitotic cyclins synthesized?
(S
OR
G2
OR
G1)
Granulation tissue
-Pic shows granulation tissue
-Also, 18 days after MI we would expect to see granulation tissue not granulomas
A 52M, is admitted to the hospital for tmt of a massive acute MI. Tmt w/O2, β-blockers,
aspirin, & reperfusion therapy is initiated. 18 days later, he develops v-fib, from which he
cannot be resuscitated. A photomicrograph of cardiac tissue from the site of infarct
obtained at autopsy is shown.
Which of the following best describes the appearance of this pt's heart?
(Granulation tissue
OR
Granuloma)
1 in 4 will have 25% β-globin function & may require occasional transfusions
-Use punnet square, works out to 1 in 4 will be affected
-Father → A A(not functional)
-Mom → A a(affected)
-Heme holds 4 so all expect one would be affected
