daisyy: 关于NBME forms 答案及解释
发信人: daisyy (Daisy), 信区: Pre_Resident_Club
标 题: 关于NBME forms 答案及解释
发信站: BBS 未名空间站 (Tue Nov 23 19:19:32 2010, 美东)
前几天看见 Medmaomier发帖找人讨论NBME form 2，要求每个参加的人把每道题的选择理由说明，同时把其他选项也加以解释。 深深觉得是个很好的主意。
下面是我做NBME form 1做的一些笔记。 我没有把notes和答案联系起来。 因为本来是记着自己看知识点的。 记得比较散，大家就是看看有没有兴趣把自己的笔记贡献出来。个人的力量有限，只有大家都贡献一点，这样每个人花的时间不多，但是可以得到一个比较详尽的NBME题目的解释。 我可以想想办法找个网站放这些笔记。
我可以负责收集整理 form 1 的题目和笔记， 因为现在我只做了form 1, 后面做了其他forms的话也可以负责收集整理其他forms的。
下面是form 1的一些笔记，还没做 NBME的请不要看， 以免影响你的测试。
For NBME form 1 block 1:
1. TB: inflammatory/immune response
epithelioid cells, multinucleated giant cells, caseation necrosis
2. Elderly abuse: Physician notify social services of the potential
abuse (Protect and report)
Child abuse--protect and report
Spouse abuse--counseling and information
3. Malignant tumor, long time berridden--develop deep venous thrombosis
4. Gastroesophageal reflex disease(GERD): Inappopriate relaxation of
lower esophageal sphincter.
Noncardiac chest pain, abdominal fullness, barret's esophagus: Glandular
metaplasia--replacement of nonkeratinized (stratified) squamous
epithelium with intestinal (columnar) epithilim in the distal esophagus.
5. Acute coronary occlusion. Hypoxia.
Consequences of hypoxic cell injury--Decreased synthesis of ATP;
Anaerobic glycolysis is used for ATP, diffusion of Na+ and water;
Decreased protein synthesis; Influx of Ca2+.
6. Parkinsonism: Degeneration/Depigmentation of neurons in substantia
nigra; deficiency of dopamine; Neurons contain intracytoplasmic,
eosinophilic bodies called Lewy bodies--ubiquninated damaged
7. decubitus: a reclining position
An S4 heart sound (see schematic) coincides with atrial contraction in
late diastole and the a wave in the jugular venous pulse (JVP; see
below). It is never a normal finding and is due to increased resistance
to ventricular filling (decreased compliance) following a vigorous
atrial contraction. It is heard best at the apex. Causes of decreased
ventricular compliance include concentric ventricular hypertrophy
(left/right) and a volume overloaded ventricle (no more room to expand).
An S4 heart sound and the a wave of a JVP are absent in atrial
8. Gout: Familial juvenile hyperuricaemic nephropathy, medullary cystic
kidney disease, phosphoribosylpyrophosphate synthetase superactivity,
and hypoxanthine-guanine phosphoribosyltransferase deficiency as seen in
Lesch-Nyhan syndrome are complicated by gout.
Superactivity of phosphoribosylpyrophosphate synthetase (PRS) is an X
chromosome-linked disorder of purine metabolism, characterized by gout
with uric acid overproduction and, in some families, neurodevelopmental
impairment. Two highly homologous isoforms of PRS (PRS1 and PRS2), each
encoded by a distinct X chromosome-linked locus, have been identified.
The juvenile/adult-onset type: Increased PRS enzyme activity at all Pi
concentrations, normal nucleotide (ADP/GDP) inhibition of enzyme
activity, normal Km for Pi activation; and increased PRS1 transcript
(northern analysis) and PRS1 isoform (isoelectric focusing-western
blotting) establish the diagnosis.
The infantile-onset type: Abnormal Pi activation of PRS enzyme activity
with increased affinity for Pi and decreased nucleotide (ADP/GDP)
inhibition of activity establishes the diagnosis.
9. Myotonic dystrophy: autosomal dominant , most common muscular
dystrophy. trinucleotide repeat disorders (CTG). Selective type 1 fibers
Facial muscle weakness, frontal balding, catareacts, heart conduction
10. Surreptitious use of insulin: plasma insulin increase, serum c-
peptide not detectable.
11. Double-stranded DNA can be denatured by heating and renatured by
cooling. Renaturation under conditions of high stringency prevent
Mismatched DNA hybridization. Renaturation is the process in which there
is anneling or matching of bases occur after denaturation..so under high
stregnity(tight control).there will be less chances of mismatching.
12. Renal agenesis occurs when the ureteric bud fails to develop.
Bilateral renal agenesis causes oligohydramnios during pregnancy--
potter's sydrome(deformed limbs, wrinkly skin, abnormal facial
13. I can see that you are up set, Please tell me what is bothering you.
The patient is number one. Always respond to the patient. Tell the
patient everything. Work on long term relationships. Listening is better
14. diphenhydramine--antihistamines, strong sedation, potent
anticholinergic agent. drowsiness,dry mouth and throat, flushed skin,
increased heart rate (tachycardia), blurred vision at nearpoint owing to
lack of accommodation (cycloplegia), abnormal sensitivity to bright
light (photophobia), pupil dilation (mydriasis), urinary retention,
constipation, difficulty concentrating, short-term memory loss, visual
disturbances, hallucinations, irregular breathing, dizziness,
irritability, itchy skin, confusion, decreased body temperature
(generally in the hands and/or feet), erectile dysfunction,
excitability, and delirium.
Cimetidine-- inhibitor of many isozymes of the cytochrome P450 enzyme.
Cimetidine interferes with metabolism of the hormone estrogen, enhancing
estrogen activity. In women, this can lead to galactorrhea, whereas in
men, gynecomastia. male sexual dysfunction. dizziness, and more rarely,
15. The follicular adenoma of the thyroid is a common benign tumor of
the thyroid gland. They present as a solitary nodule, usually as a
painless mass. It may be found during a routine physical examination. A
physician may order a nuclear medicine thyroid scan which measures
uptake of radionucleotide labelled iodine. Adenomas are usually cold
nodules since they usually take up less radioactive iodine than normal
surrounding gland. On the other hand, about 10% of cold nodules are
malignant. Conversely, hot nodules are only rarely malignant. Warm
nodules are usually functioning adenomas.
16. Toxoplasma gondii, Encephalitis, Protozoa (sporozoan)
Most common CNS space-occupying lesion in AIDS; ring-enhancing lesions
on CT . Congenital toxoplasmosis produces basal ganglia
Treatment: pyrimethamine + sulfadiazine + folinic acid (leucovorin)
19 .Fludrocortisone acetate is a synthetic corticosteroid with moderate
glucocorticoid potency and much greater mineralocorticoid potency. It is
used primarily to replace the missing hormone Aldosterone in various
forms of adrenal insufficiency such as Addison's disease and the classic
salt wasting (21-hydroxylase deficiency) form of congenital adrenal
hyperplasia. It is occasionally used to treat orthostatic hypotension as
Side effects: Sodium and water retention, Swelling due to fluid
retention (edema), High blood pressure (hypertension) .
20. Pelvic inflammatory disease (PID). Causes of PID (1) Most often due
to N. gonorrhoeae or C. trachomatis. Coexisting infection in 45% of
cases (2) Other pathogens (not STD)
PID: most common cause is N. gonorrhoeae and C.trachomatis; both present
in 45% of cases B. fragilis, streptococci, Clostridium perfringens,
Mycobacteria tuberculosis, cytomegalovirus (CMV).
Gross findings : Fallopian tubes are filled with pus.
Most common cause of hydrosalpinx: Pus resorbs, leaving a clear fluid
distending the tube.
21. Myeloperoxidase (MPO) deficiency, an autosomal recessive disorder,
differs from CGD in that both
and H2O2 are produced (normal respiratory burst). However, the absence
of MPO prevents synthesis of HOCl•
Chronic granulomatous disease (CGD) is an X-linked recessive (XR)
disorder (65% of cases) or autosomal recessive disorder (35% of cases).
The X-linked type is characterized by deficient NADPH oxidase in the
cell membranes of neutrophils and monocytes. Catalase-positive
organisms that produce H2O2 (e.g., Staphylococcus aureus) are ingested
but not killed, because the catalase degrades H2O2. The classic
screening test for CGD is the nitroblue tetrazolium (NBT) test. In this
test, leukocytes are incubated with a colorless NBT dye, which is
converted to a blue color if the respiratory burst is intact.
22. Nitroglycerin, in common with other nitrates, produces generalized
vasodilation, thereby decreasing venous return and workload on the
heart. Both arterial and venous dilation occur, although venous effects
predominate. Coronary vasodilation also occurs even in the presence of
atherosclerosis. Relaxation of vascular smooth muscle is a result of
stimulation of cyclic guanosine monophosphate (GMP) production as well
as inhibition of thromboxane synthetase, permitting preferential
formation of prostacyclin. Left ventricular end-diastolic pressure and
volume are decreased, resulting in reduction of ventricular size and
wall tension. Therapeutic doses reduce systolic, diastolic and mean
arterial blood pressure; reflex tachycardia may occur, presumably in
response to these effects.
23. Atenolol (Tenormin) is a selective β1 receptor antagonist, a drug
belonging to the group of beta blockers (sometimes written β-blockers),
a class of drugs used primarily in cardiovascular diseases. atenolol was
developed as a replacement for propranolol in the treatment of
hypertension.atenolol does not pass through the blood-brain barrier thus
avoiding various central nervous system side effects. Atenolol can be
used to treat cardiovascular diseases and conditions such as
hypertension, coronary heart disease, arrhythmias, angina (chest pain)
and to treat and reduce the risk of heart complications following
myocardial infarction (heart attack). It is also used to treat the
symptoms of Graves Disease, until antithyroid medication can take
effect. It was the main β-blocker identified as carrying a higher risk
of provoking type 2 diabetes.
Pick's disease, a personality change occurs prior to any form of memory
loss, unlike Alzheimer's, where memory loss typically presents first.
This is used clinically to determine whether patient is suffering from
Alzheimer's or Pick's.
Pick's disease is one of the causes of the clinical syndrome of
frontotemporal lobar degeneration which has three subtypes. Pick's
disease pathology is associated more with the frontotemporal dementia
and progressive nonfluent aphasia subtypes than the semantic dementia
PiD was first recognized as a distinct disease separate from other
neurodegenerative diseases because of the presence of large, dark-
staining aggregates of proteins in neurological tissue as well as the
aforementioned ballooned cells, which are known as Pick cells. Tau
protein tangles present in many affected neurons, contains only one or
as many as two of the six different isoforms of the tau protein.
24. DiGeorge syndrome,congenital thymic aplasia, and thymic hypoplasia
is a syndrome caused by the deletion of a small piece of chromosome 22.
Medical students may use the mnemonic CATCH-22 to describe DiGeorge's
syndrome, with the 22 to remind one the chromosomal abmormality is found
on the 22 chromosome, as below.
Cardiac Abnormality (especially tetralogy of Fallot)
25. Neutralization of FRs: SOD, GSH, vitamins C and E
Superoxide dismutase (SOD): Converts superoxide free radicals to
peroxide and O2
Glutathione peroxidase (enhances glutathione, GSH)
Located in the pentose phosphate pathway
Neutralizes H2O2, hydroxyl, and acetaminophen FRs
Catalase (present in peroxisomes)
Degrades peroxide into O2 and water
Vitamins as antioxidants
Antioxidants neutralize FRs by donating one of their own electrons.
(1) Stops the "electron stealing" of FRs
(2) Antioxidants remain stable and do not become an FR.
Vitamin E (fat-soluble vitamin)
(1) Prevents lipid peroxidation in cell membranes
(2) Neutralizes oxidized LDL
Vitamin C (water-soluble vitamin)
(1) Neutralizes FRs produced by pollutants and cigarette smoke
Smokers have decreased levels of vitamin C because they are used up in
neutralizing FRs derived from cigarette smoke. (2) Best neutralizer of
Neutralizes FRs in the cytosol
26. Relative risk: relative probability of getting disease in the
exposed group compare to the unexposed group.
Odds ratio: odds of having disease in exposed group divided by odds of
having disease in unexposed group.
27. Patchy leukoplakia: pre-maglinant of squamous cell carcinoma. (Other
diseases that are pre-maglinant: scar, burn scar, drainage orifice)
28. Corticosteroid stimulate type II alveolar cells to produce
29. Renovascular hypertension: most common cause of secondary
(1) Elderly men: Atherosclerotic plaque partially blocks blood flow at
the renal artery orifice.
(2) Young to middle-aged women: Fibromuscular hyperplasia occurs in
multifocal areas of the renal artery.
(1) Decreased renal arterial blood flow activates the renin-angiotensin-
aldosterone (RAA) system.
(2) Angiotensin II vasoconstricts TPR arterioles.
(3) Aldosterone increases sodium retention.
(1) Severe, uncontrollable hypertension
(2) Increased plasma renin activity (PRA) : PRA: ↑ in involved kidney; ↓
in unaffected kidney
(3) Involved kidney has increased PRA in the renal vein.
(4) Uninvolved kidney has decreased PRA.
Increased plasma volume due to aldosterone excess suppresses RAA system
in normal kidney.
(5) Epigastric bruit
Sound is due to turbulence of blood flow through the narrow renal
(a) Involved kidn:ey shows diminished size (atrophy) and delayed
(b) Renal artery has "beaded" appearance in fibromuscular hyperplasia.
30. Adrenocorticol hormone synthesis
31. Hemolytic-uremic syndrome (or haemolytic-uraemic syndrome,
abbreviated HUS) is a disease characterized by hemolytic anemia, acute
renal failure (uremia) and a low platelet count (thrombocytopenia). It
predominantly but not exclusively affects children. Most cases are
preceded by an episode of diarrhea caused by E. coli O157:H7, which is
acquired as a foodborne illness. It is a medical emergency and carries a
5–10% mortality; of the remainder, the majority recover without major
consequences but a small proportion develop chronic kidney disease and
become reliant on renal replacement therapy. The classic childhood case
of HUS occurs after bloody diarrhea caused by a strain of E. coli that
expresses verotoxin (also called Shiga-like toxin) which is known as
STEC (Shiga toxin-producing E. coli) or EHEC (Enterohemorrhagic E.
coli).The arterioles and capillaries of the body become obscured by a
resulting mesh of activated platelets which have adhered to endothelium
via large multimeric vWF. As well as consuming platelets, this mesh
thrombi destroys red blood cells as they squeeze through the narrowed
blood vessels forming schistocytes (sheared RBC's) (which is a prominent
feature used for diagnosis). This mechanism known as "microangiopathic
hemolysis" which has been likened to the effect of a cheesewire or
garotte across the vessel lumen.Histologically, the glomeruli show
thickened and sometimes split capillary walls due largely to endothelial
swelling. Large deposits of fibrin-related materials in the capillary
lumens, subendothelially, and in the mesangium are also found along with
32. Cleft lip (cheiloschisis) and cleft palate (palatoschisis), which
can also occur together as cleft lip and palate, are variations of a
type of clefting congenital deformity caused by abnormal facial
development during gestation.The development of the face is coordinated
by complex morphogenetic events and rapid proliferative expansion, and
is thus highly susceptible to environmental and genetic factors,
rationalising the high incidence of facial malformations. During the
first six to eight weeks of pregnancy, the shape of the embryo's head is
formed. Five primitive tissue lobes grow:
a) one from the top of the head down towards the future upper lip;
b-c) two from the cheeks, which meet the first lobe to form the upper
lip; (Maxillar Prominence)
d-e) and just below, two additional lobes grow from each side, which
form the chin and lower lip; (Mandibular Prominence)
If these tissues fail to meet, a gap appears where the tissues should
have joined (fused). This may happen in any single joining site, or
simultaneously in several or all of them. The resulting birth defect
reflects the locations and severity of individual fusion failures (e.g.,
from a small lip or palate fissure up to a completely malformed face).
33. Diabetes Mellitus. Vulvar prututis, vaginal discharge. Fungus
infection: pseudohyphae and budding yeast cells
34. Bovine spongiform encephalopathy: prion (No RNA, No DNA, just
35. NOS is an enzyme in the body that contributes to transmission from
one neuron to another, to the immune system and to dilating blood
vessels. It does so by synthesis of nitric oxide (NO) from the terminal
nitrogen atom of arginine in the presence of NADPH and dioxygen (O2).
NOS is the only known enzyme that binds flavin adenine dinucleotide
(FAD), flavin mononucleotide (FMN), heme, tetrahydrobiopterin (BH4) and
NO activates Guanylate cyclase, which induces smooth muscle relaxation
Increased intracellular cGMP, which inhibits calcium entry into the
cell, and decreases intracellular calcium concentrations.
Activation of K+ channels, which leads to hyperpolarization and
Stimulates a cGMP-dependent protein kinase that activates myosin light
chain phosphatase, the enzyme that dephosphorylates myosin light chains,
which leads to smooth muscle relaxation.
36. esophageal varices are extremely dilated sub-mucosal veins in the
lower esophagus. They are most often a consequence of portal
hypertension, commonly due to cirrhosis; patients with esophageal
varices have a strong tendency to develop bleeding.
37. Malabsorption. (Crohn's disease, celiac disease, Irritable Bowel
syndrome?). Lack of vitamin D. Ca decrease, Phosphorus decrease (cuz
can't absorb them from the intestinal tract which is controlled by
vitamin D), AP increase (increased bone resporbtion), PTH increase.
38. Major depression: symptoms for at least two weeks. No motivation,
anhedonia(快感缺乏), feelings of worthlessness, decreased concentration,
weght loss or gain, depressed mood, recurrent thoughts, insomnia or
hypyesomnia, phychomotor agitationor retardation, somatic complains,
delusions or hallucinations, loss of sex drive.
39. Acetysalicylic Acid (ASA, Aspirin). Causes irreversible inhibition
of COX. Covalent bond vis aectylation of a serine hydroxyl group near
the active site. Antiplatet aggregation(low dose), analgesia and
antipyresis (moderate dose), antiinflamatory (high dose). Uric acid
elimination: low to moderate dose: decrease tubular secretion-->
hyperuricemia, high dose: decrease tubular reabsorption--> uricosuria.
Acid-base and eletrolyte balance.Low dose: increase respiration--
>respiratory alkalosis; toxic dose: inhibits respiratory center-->
decrease respiration--> metabolic acidosis.
Side effects:gastrointestinal irritation: gastritis, ulcer, bleeding.
Salicylism: tinnitus, vertigo, decrease hearing--often first signs of
toxicity. Bronchoconstriction, hypersensitivity (triad: asthma, nasal
polyp, rhinitis), reye syndrome (encepholopathy), increased bleeding
time: increased prothrombin time; chronic use associated with renal
dysfunction, many drug interaction (ethanol increased gastrointestinal
bleeding, increase effects of sulfonyurea and warfarin, decrease effects
overdose and management: extention of toxic actions decribed above, plus
a high dose vasomotor collapse occurs, with both respiratory and renal
failure. No specif antidote. Management includes gatric lavage(+/-
actiavted charcol) plus ventilatory support and symptomatic management
of acid-base and eletrolyte imbalance, and the hyperthermia and
resulting dehydration. (ASA follows zero-order elimination kinetics at
toxic doses .)
Auranofin is an organogold compound classified by the World Health
Organization as an antirheumatic agent. (Gold salt)
It has the brand name Ridaura. decrease lysosomal and macrophage
functions. Side effects: dermatitis, hematotoxicity, nephrotoxicity.
40. Hight and weight correlation. Position correlation.
41. Post-marketing drug studies can detect rare serious adverse events.
42. To improve its immunogenicity for children and adults and to make it
suitable for routine immunization of infants against typhoid fever, the
capsular polysaccharide of Salmonella typhi (Vi) was bound to the B
subunit of the heat-labile toxin (LT-B) of Escherichia coli or the
recombinant exoprotein A (rEPA) of Pseudomonas aeruginosa. The
conjugates elicited higher levels of antibodies.
Polysaccharide-protein conjugates as vaccines have proven to be very
effective in preventing Haemophilus influenzae type b infections in
43. Veterbral angiogram: Hemorrhage of anterior inferior cerebellar
44. if G is negative, reaction goes forward, if G is positive, reaction
goes backward, so the net value from the first 3 reactions is -7, that
makes the direction goes from X to Y, the last reaction G is positive,
so more Y should be made, overall, Y is made more.
45. Case fatality rate: is the ratio of deaths within a designated
population of people with a particular condition, over a certain period
46. Vasectomy is a minor surgical procedure wherein the vasa deferentia
of a man are severed, and then tied/sealed in a manner which prevents
sperm from entering the seminal stream (ejaculate). Vasectomy should not
be confused with castration (male), which is the surgical removal of
one's testicle(s). Sperm is matured in the epididymis for about a month
once it leaves the testicles. Early failure rates, i.e. pregnancy within
a few months after vasectomy typically result from having unprotected
intercourse too soon after the procedure. Late failure, i.e. pregnancy
after recanalization of the vasa deferentia, has been documented but is
very rare.Most physicians and surgeons who perform vasectomies recommend
one (sometimes two) post-procedural semen specimens to verify a
successful vasectomy. Sexual intercourse can be resumed as soon as it is
comfortable, usually in about a week. However, pregnancy is still
possible as long as the sperm count is above zero. Another method of
birth control must be used until a follow-up sperm count test two months
after the vasectomy (or after 10 to 20 ejaculations over a shorter
period of time). Once the sperm count is zero, no other birth control
method is necessary.
Illustration of the intracellular signalling pathways for P2Y receptors.
(a) Mechanisms that use the phospholipase C (PLC) pathway of
intracellular signalling are mediated by G-proteins, which are activated
when the agonist binds to the cell-surface P2Y receptor. G-protein-
mediated activation of PLC stimulates the breakdown of
phosphatidylinositol 4,5-bisphosphate (PIP2) to form inositol 1,4,5-
trisphosphate (IP3) and diacylglycerol (DAG). IP3 releases Ca2+ from
intracellular stores and DAG activates protein kinase C (PKC), which
together modify the activity of cellular proteins. (b) Mechanisms that
generate cAMP by activation of adenylyl cyclase are also mediated by G-
proteins. cAMP acts intracellularly to activate protein kinase A (PKA),
which then phosphorylates substrates such as members of the cAMP
response element binding (CREB) protein family.
48. The CD5 antigen is a T-cell associated marker that is also usually
expressed by two B-cell neoplasms, chronic lymphocytic leukemia/small
lymphocytic lymphoma and mantle cell lymphoma. Expression of the CD5
antigen by neoplastic cells often is considered a diagnostic criterion
for B-cell chronic lymphocytic leukemia (B-CLL).
49. See 25
50. An aortic dissection may also involve abnormal widening or
ballooning of the aorta (aneurysm).
The exact cause is unknown, but risks include atherosclerosis (hardening
of the arteries) and high blood pressure. Traumatic injury is a major
cause of aortic dissection, especially blunt trauma to the chest.
Hitting the steering wheel of a car during an accident is a common
traumatic cause. The symptoms usually begin suddenly, and include
severe chest pain. The pain may: Be described as sharp, stabbing,
tearing, or ripping; Be felt below the chest bone, then moves under the
shoulder blades or to the back; Move to the shoulder, neck, arm, jaw,
abdomen, or hips
Change position -- pain typically moves to the arms and legs as the
aortic dissection gets worse.
Other symptoms may include:
Changes in thought ability, confusion, disorientation ; Decreased
movement in any part of the body ; Decreased sensation in any part of
the body ;Dizziness ;Dry mouth ;Dry skin ;Fainting ;Nausea and vomiting
;Pallor ;Profuse sweating (clammy skin) ;Rapid, weak pulse ;Shortness of
breath -- difficulty breathing when lying flat (orthopnea)
Exams and Tests
The health care provider will take your family history and listen to
your heart, lungs, and abdomen with a stethoscope. A "blowing" murmur
over the aorta, a heart murmur, or other abnormal sound may be heard.
There may be a difference in blood pressure between the right and left
arms, or between the arms and the legs. (dissection at bifurcation)
There may be low blood pressure, bulging neck veins, or signs resembling
a heart attack. There may be signs of shock, but with normal blood
Aortic valve regurgitation
(1) Due to aortic valve ring dilation
(2) A radiograph or echocardiogram shows widening of the aortic valve
acute aortic dissection has an early mortality as
high as 1% per hour,' with nearly two thirds of
deaths in cases of proximal dissection resulting
from the extension of the dissection into the aortic root
producing hemopericardium and cardiac tamponade.
The hemopericardium complicating proximal aortic dissection develops as
a result of blood leaking into the pericardial
space from the false lumen as it dissects back to the
※ 修改:·daisyy 於 Nov 23 19:30:14 2010 修改本文·[FROM: 69.134.]