uWorld 2 Flashcards
present self antigen, tumor antigen, or antigen synthesized by the cell due to viral infection
proteins in cytoplasm are degraded molecules and subsequently routed to the cell surface via the golgi apparatus
never processed w/in acidified lysosomes
MHC Class I
endogenous pathway of antigen presentation
found on surface of most nucleated cells of human body
integrins are necessary for what
binding of inflammatory cells to vascular walls during the process of TRANSMIGRATION through the endothelial layer from the bloodstream to the tissues
how does MHC class II antigen presentation happen
material in environment is taken up by APC and degraded by acidification after endosome-lysosome fusion or phagosome-lysosome fusion
MHC-II is synthesized in roughER and routed to endosomes by the Golgi apparatus
MHC-II is antigen binding site blocked by invariant chain- guides molecule during sorting and fusion of vesicle with MHC to phago-lysosome
what is humoral hypercalcemia of malignancy (HHM)
caused by secretion of parathyroid hormone related protein (PTH-rP)
causes increased bone resorption and decreased renal exertion of calcium
polyuria, nephrolithiasis, GI and neuropsychiatric symptoms`
acute onset of mental status change is most suggestive of what (delirium, dementia, or depression)
delirium- a reversible, acute confusional state involving a reduced or fluctuating level of consciousness with difficulty sustaining attention and impaired memory and executive function
what is a brief psychotic disorder
sudden onset of at least one positive psychotic symptoms (delusions, hallucinations, disorganized speech or behavior) lasting form one day to a month
typically alert and oriented
what is type II (beta) error
FALSELY conclude there was NO increased risk
probability of a type II error is related to how much POWER a study has to detect a difference when a difference actually exists (power = 1-beta)
SAMPLE SIZE and power are related in that studies with a large sample size have a greater power
if the RR obtained in the first study was similar to the one obtained in the meta-analysis it is unlikely what what was present in the study
design flaws (i.e. poor blinding, researcher expectancy)
what is Berkson’s Bias
election bias that van be created by selecting hospitalized patients as the control group (b/c they are less healthy than normal population)
what are Gardos channel blockers
calcium-dependent (Gardos) potassium channel regulators the transport of potassium and water through the red blood cell membrane- when blocked, potassium and water efflux if reduced, preventing dehydration of erythrocytes and reducing the polymerization of HbS
what is the mechanism most likely responsible for the decreased genes expression seen in huntington disease
HISTONE DEACETYLATION- thus silencing genes necessary for neuronal survival expansion of the huntingtin protein results in a GAIN-OF-FUNCTION that leads to pathological interaction with other proteins, including various transition factors TRANSCIPTIONAL REPRESSION (SILENCING) is one of the mechanisms by which mutated huntingtin is thought to cause disease
loss of hunting tin protein results in what
embryonic death
what causes a low volume of distribution (3-5 liters) of a drug (i.e. drug stays in plasma compartment)
large molecular weight
bound extensively to plasma proteins
highly charged (hydrophilic)
when would one see a volume of distribution of 14-16 liters
if the drug has a small molecular weight but is hydrophilic (charged)
(it can distribute into the plasma volume plus interstitial volume)
when does a drug exhibit a higher volume of distribution much higher than total body waster volume
drugs that avidly bind the tissues
how can thiamine deficiency be diagnosed
if baseline ERYTHROCYTE TRANSKETOLASE ACTIVITY is low but increases after thiamine pyrophosphate
what is the function of DNA polymerase delta
elongates Okazaki fragments of the lagging strand
fragments are later joined by the enzyme DNA ligase
snRNA is synthesized by what
RNA polymerase II (along with mRNA and miRNA)
what are anti-smith antibodies against
snRNPs (complexes of snRNA with proteins that are essential component of spliceosomes which remove introns from pre-mRNA forming m-RNA)
what is the first-line antidepressant for major depressive disorder
SSRI (block the serotonin transporter)
to ensure that that investigators do not miss a difference between drug B and standard of care (if a difference truly exists) what do you want to maximize?
power (power = 1-beta)
what is a type 1 error
reject the null hypothesis when the null hypothesis is really true (finding a statistical significance b/w 2 groups that doesn’t exist)
if p is less than a (0.05) then it is statistically significant
what is seen microscopically in seborrheic keratosis
sells resembling basal cells, with variable pigmentation
hyperkeratosis (thickening of status corneum)
keratin containing cysts
what is discoid lupus erythematous (DLE)
thick, scaly, discoid plaque that erupt on unexposed skin and may result in scarring
systemic disease in not present in most patients with DLE
what is a xanthelasma
common yellowish macule, papule, or plaque found on the EYELID and is often associated with hyperlipidemia
what are most cases of Rett syndrome due to
de novo mutations in the X-linked MECP2 gene
what is seen in Rett syndrome
mainly girls normal development to 5-18 months loss of motor and language skills development of stereotypical hand movements (wringing) DECELERATION of HEAD GROWTH
what is the inheritance of Lesch-Nyhan syndrome
x-linked recessive
what is stereotypic movement disorder
characterized by stereotypical, purposeless motor behavior that begins in early development and is not better explained by another neurodevelopment or genetic disorder
what is the functional residual capacity
point where the tendencies of the chest wall to expand and the lung to collapse oppose one another
creating an NEGATIVE INTRAPLEURAL PRESSURE of approx -5cm H2O
(during inspiration intrapleural pressure gets even more negative and thus induces a negative alveolar pressure drawing air into lungs)
what is the most commonly featured bone
clavicle
the clavical is the point of origin or insertion for what msucles
deltoid- inferolateral aspect pectorals major- inferomedial aspect subclavius- inferolateral aspect sternohyoid- inferomedial aspect trapezius- superolateral aspect sternocleidomastoid- superomedial aspect
the major and minor rhomboid muscles originate and insert where, what do they do
originate on the vertebral spines
insert on the medal border of the scapula
cause retraction of the scapulae
serratus anterior muscle originates where and inserts where, what innervates it, what problem is caused by loss of innervation
originates- laterally on 1-8 ribs
inserts- meidal aspect of scapula
innervated by long thoracic nerve, injury causes winged scapula
where does the sternoclavicular ligament attach and what does it do
attach the clavicle to the manubrium
hold medal side of medial fragment (of a fractured clavicle) in place
where does the subclavius muscle originate and what is its function
originated on the first rib and inserts on the inferior lateral aspect of clavicle
functions to displace clavicle inferiorly
where does the trapezius originate and insert
cervical spinous processes and insert on the lateral third of classical
pulls lateral fragment (of a fractured clavicle) superiorly but the combined traction from arm weight and pectorals major overcomes trap
what causes superior displacement of medal fragment of the glacial following a fracture
what causes inferior displacement of the lateral fragment of the clavicle after a fracture
sternocleidomastoid- superior displacement
weight of the arm and pectorals major muscle cause inferior displacement
what happens to EPO in COPD and why
erythropoietin production increased
smokers have chronic bronchitis (decreasing the diameter of conducting airways) and centrilobular emphysema (dilating the alveolar air places so that there is insufficient contact b/w the airspace’s and deoxygenated blood in alveolar capillaries) both which cause hypoxia
smoking can independently cause hypoxia by increasing concentration of carboxyhemoglobin
hypoxia is sensed by renal cortex that synthesize and release EPO
in COPD what happens to expiratory flow rate, functional residual capacity,
Expiratory flow rate- decreased
FRC- increased
right ventricular afterload- increased
left ventricular compliance- not directly affected
where do the ureters course anteriorly to the external iliac artery
at or just after the bifurcation of the common iliac artery
external iliac continues along the pelvic brim and passes under the inguinal ligament to become there femoral artery (it does not enter the true pelvis)
where does the ureters cross anteriorly to the internal iliac artery
ureters gain access to the pelvis by crossing over the anterior surface of the common iliac artery near its bifurcation, at this point the ureter lies medial to the ovarian vessels and anterior to the internal iliac artery (WITHIN THE TRUE PELVIS)
what crosses over the anterior surface of the ureter midway form the kidney to the pelvic inlet
gonadal artery and vein
genes for extended spectrum beta lactamases (ESBL) are found where
PLASMIDS
what is the treatment of choice for extended spectrum beta lactamase producing organisms
CARBAPENEMS
porin mutations can confer resistance to what antibiotics and what organisms utilize this
penicillin and amino glycoside resistance
gram negative organisms (Pseudomonas)
mutations in DNA gyrate can lead to resistance to what drugs
fluoroguinolones
what is cryoprecipitate
contains only cold-soluble proteins (Factor 8, fibrinogen, cWF, vitronectin)
what toxin from ETEC is like cholera toxin in striation and mode of action (explain)
LT (enterotoxin)
increases intracellular cAMP in gut mucosal cells by Gs
endotoxin release induces an inflammatory response mediated by what
tumor necrosis factor-alpha and interleukin-1 secreted from activated macrophages
when does one see “stacked brick” intestinal adhesion
enteroaggregative Escherichia coli (EAEC)
organisms adhere to jejunal, ill, and colonic mucosa in an aggregative, or stacked-brick, pattern and do not invade
implicated in persistant diarrhea in infants in developing countries
the steric bud gives rise to what
collecting system of the kidneys (collecting tubules and ducts, major and minor calyces, renal pelvis, ureters
the metanephric blastema gives rise to what
glomeruli, Bowman’s space, proximal tubules, loop of hence, distal convoluted tubule
the structures of the mesonephros become what in males and females
males- Wolffian ducts (ductus deference and epididymis)
females- regresses and becomes vestigial Gartner’s ducts
decompensated heart failure in the setting of a recent viral infection
DIALTED CARDIOMYOPATHY (dilated with abnormal systolic ventricular function)
regional wall nation abnormality is suggestive of what
ischemic heart disease
causes volume overload resulting in eccentric hypertrophy
glucagon works via what receptor
Gs
what is the most common lung tumor and what does one see in it
hamartoma (pulmonary chondroma)
contain islands of mature HYALINE CARTILAGE, fat, smooth muscle, clefts lined by respiratory epithelium
presents as a “COIN LESION” with “POPCORN CALCIFICATIONS”
what is the best description of thyroid peroxidase enzyme
thyroglobulin iodination
NOT thyroxine to triiodothyronine conversions b/c only 20% T3 comes from thyroid rest is converted by iodothyronine deiodinasefrom T4
central lines are inserted how
in neck (internal jugular vein) or chest (subclavian vein) and is advanced until the catheter tip enters the SVC
the SVC is derived from what
common cardinal veins
what forms the descending aorta
fusion of the embryonic right and left dorsal aortas
if a pt is started on meds and 10 days later they get joint pain and a pruritic skin rash that show fibrinoid necrosis and neutrophil infiltration what probably happened and what finding is seen in the pt
serum sickness (happens after administration of chimeric monoclonal antibodies or nonhuman immunoglobulins decreased serum C3 level
is leukocyte alkaline phosphatase is low
chronic myelogenous leukemia
what are the findings of an accessory nipple
due to FAILURE OF INVOLUTION OF THE MAMMARY RIDGE
what is an acrochorda
a skin tag
benign and often pedunculate outgrowths of notable skin
develop in locations of excess friction like beneath the breasts
BRCA1 and BRCA2 are are involved in what and what is the inheritance
repair of double stranded DNA breaks
autosomal dominant
what breast cancer mutation is associated with abarent signal transduction
HER2
what organism looks “cotton candy” like on Pap smear and may be an incidental finding in patients with IUD
Actinomyces
what cells predominate Pap smear of postmenopausal and postpartum women
paranasal cells- round cells with a basophilic cytoplasm, finely granular chromatin in their nuclei, no visible nuclei, high N/C ratio
“fried eggs” with a large “central egg yolk”
what cell presence in a Pap smear indicated adequate sampling
glandular endocervical cells
