Uworld 23

Front 1

Rough ER

Back 1

-rER functions include protein modification, folding, and transfer

-rER is well-developed in protein-secreting cells

-vs. smooth ER lacks surface ribosomes – functions in lipid synthesis, carbohydrate metabolism, and detoxification of harmful substances

Front 2

LH vs. estrogen/progesterone

Back 2

-as follicular/proliferative phase advances, progressive rise in serum estradiol is seen

-high levels of estrogen in the late follicular phase have a positive feedback effect on LH production, causing a very high LH level (luteal surge).

-progesterone secretion increases AFTER ovulation due to formation of the corpus luteum.

Front 3

Wilson's disease

Back 3

-wilson's disease can cause cystic degeneration of the putamen, as well as damage to other basal ganglia structures

-the putamen is located medial to the insula, and lateral to the globes pallids on coronal sections

Front 4

Projection

Back 4

-projection refers to transplanting one's unacceptable impulses or affect onto another person or situation.

-projection is an immature defense mechanism

Front 5

Prospective cohort study

Back 5

-prospective cohort studies are organized by selecting a group of individuals (cohort), determining their EXPOSURE STATUS, and then following them over time for development of disease of interest.

-vs. case-control study: designed by selecting patients who have a DISEASE (case) and without the disease (control), and then determining their PREVIOUS EXPOSURE status.

Front 6

Reaction formation

Identification

Splitting

Back 6

-reaction formation: redirection of an unacceptable impulse into its opposite
--e.g., former alcoholic tries to ban alcohol sales

-identification: modeling one's behavior after someone who is perceived to be more powerful – behavior may be admirable or non-admirable.
--e.g., child of abusive father becoming a child abuser.

-splitting: unconscious belief that people are either all good or all bad
--hallmark of borderline personality disorder

Front 7

Sympathetic effects on pancreatic beta-cells

Back 7

-sympathetic effect on beta cells can be either inhibitory or stimulatory, depending on the type of receptor activation.

-stimulation of ALPHA receptors inhibits insulin release, while stimulation of BETA receptors stimulates insulin secretion.

-so giving an alpha-blocker, like phenoxybenzamine, allows epinephrine (which can bind to both alpha and beta receptors) to bind only to beta-receptors.

--therefore, giving an alpha-blocker and then epinephrine would increase insulin release.

--vs. epi usually results in decreased insulin under physiologic conditions

Front 8

Minimal alveolar concentration (MAC)

Back 8

-minimal alveolar concentration is a measure of potency of an inhaled anesthetic

-it is equal to the concentration of the anesthetic in the alveoli that renders half of patients unresponsive to painful stimuli (ED50)

-potency is inversely proportion to the MAC – the lower the MAC, the more potent the anesthetic.

Front 9

Zidovudine (ZDV, AZT) and AIDS transmission to child

Back 9

-zidovudine is a retroviral reverse transcriptase inhibitor ("viral enzyme inhibitor drug")

-studies show that maternal prophylaxis during pregnancy with zidovudine reduces risk of perinatal transmission by about 2/3 in HIV-positive women who have not previously received anti-retroviral therapy

Front 10

Fetal presentation of HIV

Back 10

-oral thrush, interstital pneumonia, and severe lymphopenia during first year of life are consistent with vertical transmission of HIV-1 from mother to fetus.

Front 11

Amphotericin B – adverse effects

Back 11

-amphotericin B is a drug of choice for many systemic mycoses (e.g., disseminated histoplasmosis)

-however, hypokalemia and hypomagnesemia are common electrolyte disturbances in patients undergoing treatment with amphotericin B

--these electrolyte changes reflect increased distal tubular membrane permeability caused by amphotericin B

--profound hypokalemia can cause ventricular tachycardia or fibrillation

Front 12

Finding the Inferior Vena Cava

Back 12

-the inferior vena cava (IVC) is formed by the union of the right and left common iliac veins at the level of L4-L5.

-the renal arteries and veins can be used as landmarks because they lie at the level of L1.

-at the level of L1, the IVC lies just anterior to the right renal artery, and to the right of the abdominal aorta.

-the IVC returns venous blood to the heart from the lower extremities, portal system, and abdominal and pelvic viscera

Front 13

Prolactinoma

Back 13

-prolactinomas are the most common pituitary tumors

-in females, prolactinomas typically cause amenorrhea and galactorrhea

--this reproductive dysfunction occurs because high levels of prolactin suppress gonadotrophin-releasing hormone (GnRH) from the hypothalamus
--> hypogonadism, anovulation, amenorrhea

-the direct effect of prolactin on the breasts causes milk discharge (galactorrhea)

-if hyper-prolactinmeia is not treated, prolonged hypogonadism (low estrogen) causes accelerated bone loss, exactly as occurs in post-meonpausal osteopenia/osteoporosis.

--low bone density puts patient at high risk for fragility fractures (aka, pathologic factors).

-so in a patient with a long-standing prolactinoma, fractures due to low bone density and vaginal dryness due to estrogen deficiency may be seen.

Front 14

Neurophysins

Back 14

-neurophysins are carrier proteins for oxytocin and vasoprssin (ADH)

-oxytocin and vasopressin are carried by unique neurophysins from their site of production (cell bodies of paraventricular and supraoptic nuclei) to site of release (axon terminals of posterior pituitary)

-point mutations in neurophysin II underlie most cases of hereditary hypothalamic diabetes insipid us, a disorder resulting from insufficient ADH release into systemic circulation --> copious fluid loss via renal excretion.

Front 15

Riboflavin

Back 15

-riboflavin (vitamin B2) is precursor of the enzymes FMN and FAD.

-FAD partipates in tricarboxylic acid cycle (Krebs cycle) as coenzyme of succinate dehydrogenase, which converts succinate into fumarate.

-"Tender Loving Care For Nancy"

Front 16

Why human skin wrinkles with aging

Back 16

-as consequence of aging, fine skin wrinkles appear secondary to decreased synthesis and net loss of dermal elastin and collagen.

-i.e., decreased collagen fibril production

-proline hydroxylation indirectly decreases during aging because amount of end product (collagen) decreases

Front 17

P. aeruginosa

Back 17

-pseudomonas aeruginosa is a non-lactose fermenting gram-negative organism

-p. aeruginosa is common cause of UTIs in patients with indwelling bladder catheters

Front 18

Coccidioides immitis

Back 18

-infection with coccidioides immits can be asymptomatic or cause pulmonary disease, ranging from flu-like illness to chronic pneumonia

-coccidioides immitis cases disseminated disease in immunocompromised patients

--spherules containing endosperm are found in tissue samples

Front 19

Congenital hypothyroidism

Back 19

-congenital hypothyroidism presents soon after birth, with hypotonia, poor feeding, jaundice, macroglossia (big tongue), constipation, and UMBILICAL HERNIA

-congenital hypothyroidism should be diagnosed as early as possible to prevent development of mental retardation

Front 20

Fetal lung maturity

Back 20

-phospholipids, including dipalmitoyl phosphatidylcholine, are a major component of pulmonary surfactant

-the amniotic fluid lecithin (phosphatidylcholine) to sphingomyelin ratio (L/S ratio) is measured in order to assess fetawl lung maturity

-the fetal lungs are considered mature when they produce adequate surfactant to yield an L/S ratio GREATER THAN 2.

Front 21

Using Triptans as migraine therapy

Back 21

-migraine headaches are unilateral; have a pulsating or throbbing quality; and are associated with photophobia, phono phobia, and nausea

-triptans are 5-HT-1B/5-HT-1D agonists that are used as abortive therapy during an acute migraine

-vs. beta-blockers, anti-depressants (amitriptyline and venlafaxine) and anti-convulsants (valproate, topiramate) are commonly sued for migraine prophylaxis.

Front 22

Mitral regurgitation due to rheumatic heart disease

Back 22

-mitral regurgitation results in a blowing holosystolic murmur – heard best over the cardiac apex, with radiation to the axilla

-a history of knee swelling as a child in an immigrant (from Cambodia) points toward rheumatic heart disease as the cause of mitral regurgitation

-while uncommon in developed countries, rheumatic heart disease is still prominent globally, and is almost always associated with mitral valve disease.

-although mitral STENOSIS can also occur in rheumatic heart disease, patients generally present in middle age (vs. young presentation in mitral regurgitation).

-in older patients, mixed mitral disease (stenosis and regurgitation) becomes increasingly frequent

-rheumatic fever is caused initially by group A strep (pyogenes) and development of auto-IgA antibodies via molecular mimicry by the streptococcal M protein.

Front 23

Warfarin metabolism

Back 23

-many drugs can induce (accelerate) hepatic metabolism of warfarin, leading to reduced anticoagulation and enhanced thrombotic risk

--these inducers include antibiotics (rifampin, griseofulvin) and anti-ipleptic durgs (barbiturates, carbamazepine, phenytoin)

-Warfarin metabolism may also be INHIBITED by antibiotics (trimethoprim, isoniazid, fluconazole), as well as other drugs such as cimetidine.

--inhibition of warfarin metabolism can increase risk of bleeding

Front 24

Fas receptor

Back 24

-the fas receptor acts to initiate the extrinsic pathway of apoptosis

--mutations involving the Fas receptor or Fas ligand can prevent apoptosis of auto-reactive lymphocytes, thereby increasing the risk of autoimmune disorders such as systemic lupus erythematosus.

Front 25

Risk for angiosarcoma

Back 25

-axillary lymph node dissection (e.g., after mastectomy) is risk factor for developing chronic lymphedema of ipsilateral arm

-chronic lymphedema predisposes to the development of angiosarcoma (Stewart-Treves syndrome)

Front 26

Neurofibroma

Back 26

-neurofibromas are soft rubbery asymptomatic cutaneous nodules that commonly appear during second and third decades of life

Front 27

Hemangioma

Back 27

-hemangiomas are benign congenital vascular neoplasms that affect infants

-hemangiomas often enlarge in the months following birth before spontaneously involuting

-"cavernous hemangioma" = deep hemangioma