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1 USMLE NOTES > last weeks > Flashcards

last weeks Flashcards

1
Q

stop codons?

what binds them?

A

UGA
UAG
UAA

NOT any tRNAs. They are bound by Releasing Factors, RF1, RF2, RF3.

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2
Q

Sturge Weber inheritance and mnemnonic

A

S - Sporadic, stain, and seizures
T - Tram track calcifications of the white matter
U - Unilateral
R - Retardation
G - GNAQ gene activating mutation.
E - Epilepsy,
SPORADIC, non-inherited developmental disroder

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3
Q

Von Geirke disease defect

What sugars should be avoided in von gierkes disease

A

Fructose and galactose - they increase the Glucose 6 phosphate concentration, VG disease is a Glucose 6 phosphatase deficiency.

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4
Q

Pompe Disease defect

A

Lysosomal acid 1,4 glucosidase with 1,6 glucosidase activity, aka acid maltase

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5
Q

Cori disease

A

Debranching enzyme 1,6 glucosidase

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6
Q

What is the use and mechanism of

Fomepizole

A

Fomepizole inhibits alcohol dehydrogenase.

Used to treat Methanol, Isopropyl alcohol, or Ethylene Glycol poisoning

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7
Q

Treatment for Salicylate overdose

A

NaHCO3, sodium bicarb, to alaklinize the urine,

also helps alkalinize the blood to counter the met acidosis from salicylate

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8
Q

Treatment for TCA overdose

A

NaHCO3, sodium bicarb, alkalinize urine, and the increased Na+ helps prevent TCA binding to Na channels.

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9
Q

Posterior Inferior Cerebellar Artery Infarct

A

Lateral medullary syndrome, Wallenberg syndrome

Loss of pain and temp sensation on ipsilateral face
Loss of pain and temp sensation from contralateral body

Speech and swallowing difficulty,
Dysarthria and Dysphagia
Loss of ipsilateral gag reflex
Hiccups

Ipsilateral horner syndrome

Vertigo
Nystagmus
Ipsilateral clumsiness, ataxia, and intention tremor.

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10
Q

Medial medullary syndrome

A

Infarct of penetrating branches of the Anterior spinal artery or basilar artery in the medulla.

Lesions to:
- Corticospinal tract in the pyramids - hemiparesis and UMN lesion to contralateral body. (decussates just below the pyramids)

  • Medial lemniscus - Loss of vibration, fine touch, and proprioception from contralateral arm and leg
  • Hypoglossal nucleus and nerve - Tongue weakness and atrophy, deviates toward the lesion, a LMN lesion of hypoglossal
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11
Q

Lesion at the Genu of the internal capsule

A

Paralysis of the contralateral lower half of face.

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12
Q

Lesion to the posterior limb of internal capsule

A

Combined motor and sensory loss of contralateral body.

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13
Q

Lesion to the Ventral Posterior Thalamus

A

Loss of sensation from the contralateral face and body.

VPL - body sensation
VPM - face sensation from CNV.

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14
Q

Paraneoplastic cerebellar degeneration

A

Antibodies against purkinje cell antigens

Small cell lung cancer - anti-Hu
Breast and uterine cancers anti-Yo
Hodgkin lymphoma anti-Tr

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15
Q

Paraneoplastic encephalomyelitis

A

Small cell lung cancer

Anti-Hu in neurons

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16
Q

Opsoclonus-myoclonus ataxia syndrome

A

Dancing eyes, dancing feet.

Neuroblastoma in children
SCLC in adults

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17
Q

Anti-NMDA receptor encephalitis

A

Pyschiatric change
Memory loss
seizures
dyskinesia

Ovarian teratoma

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18
Q

Sterile platelet thrombi on the heart valves

A

Non-bacterial thrombotic endocarditis

SLE

Adenocarcinomas, especially pancreas, as paraneoplastic
Non-bacterial thrombotic endocarditis

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19
Q

Maternal virilization during pregnancy

A

Placental aromatase deficiency
XX female fetus
presents with ambiduous genetalia
inability to synthesize estrogen from androgens

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20
Q

Gabapentin and Pregabalin mechanisms and use

A

Inhibit voltage gated Calcium channels
and
Increase presynaptic GABA release.

Rx:
Fibromyalgia
Post-herpetic neuralgia
sometimes as antiepileptics

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21
Q

Vigabatrin and Tiagabine mechanisms and use

A

Vigabatrin inhibits GABA transaminase, increasing CNS GABA levels

Tiagabine inhibits synaptic GABA reuptake.

Used as adjunct treatments for partial seizure disorders.

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22
Q

Cyclobenzaprine

A

Unclear mechanism inhibiting muscle stretch refelx in spinal cord.
Used to treat acute spasms due to injury or inflammation
Strong antimuscarinic effects.

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23
Q

Dandy Walker malformation

A

Agenesis of the cerebellar vermis
Cystic enlargement of 4th ventricle
associated with noncommunicating hydrocephus and psina bifida.

Idiopathic or Rubella or Fetal Alcohol associated.

24
Q

Primary sclerosing cholangitis is associated with

A

Middle aged men with IBD

Cholangiocarcinoma
Gallbladder cancer
Ulcerative colitis
and is p-ANCA positive
increased IgM
25
Q

Primary billiary cirrhosis is associated with

A

Middle aged women with autoimmune diseases

autoimmune conditions
sjogrens, RA
anti-mitochondrial antibodies
increased IgM

26
Q

refeeding syndrome

A

when previously malnourished patients are fed with high carbohydrate loads, a rapid fall in serum phosphate, magnesium, and potassium ensues along with an increase in extracellular fluid volume.

27
Q

Lateral cerebellar lesions

A

Ipsilateral difficulty with moving the arms and legs

Propensity to fall towards the ipsilateral side

28
Q

Medial cerebellar lesions

A

Affect trunk. Truncal ataxia.
Wide based ataxic gait
Nystagmus
Bilateral defects of proximal limb muscles.

29
Q

General cerebellar lesion signs

A

ataxia

dysmetria - ‘past pointing’

dysdiadochokinesia

Intention tremor

Instability on standing with feet together whether eyes are opened or closed

30
Q

Romberg sign

A

Patient can stand with feet together and eyes are open,
but once eyes close and they remove visual input they fall,
because the proprioceptive sense is defective.
ie sensory ataxia.

31
Q

Naked DNA viruses

A

PapPPA

Papillomavirus
Polyomavirus
Parvovirus
Adenovirus

32
Q

Naked RNA viruses

A

Reovirus - You get naked to jump in the double stranded reo grand

Picornaviruses - Ornas always naked

Caliciviruses - Khalisi naked

Hepevirus - HEV is the only naked hep virus

33
Q

DNA Mismatch repair

A

MSH1 MSH2, seen in HNPCC, lynch syndrome

34
Q

Nucleotide excision repair

A

Repair of thymidine dimers.
Xeroderma pigmentosum

Endonuclease cuts out several nucleotides around the dimer

Polymerase fills it
Ligase seals it

35
Q

Base excision repair

A

Repairs deaminated cytosines (uracils)

Glycosylase excises just the base –> Apurinic/Apyrimidinic site

AP-Endonuclease cleaves th 5’ end of the sugar phosphate backbone

Lyase cleaves the 3’ end

Polymerase replases the nucleotide

Ligase seals it

36
Q

Nonhomologous end joining

A

Double stranded break repair.

Ataxia telangiectasia

Cerebellar degeneration (Ataxia), Spider Angiomas (telangiectasia), IgA, IgG, and IgE deficiency
Increased AFP
Increased risk for lymphomas and leukemias.

37
Q

Alport Syndrome

A

Mutation in type 4 collagen.

Retinopathy, Lens dislocation, and/or Cataracts

Glomerulonephritis

Sensorineural deafness

“Can’t see, can’t pee, can’t hear high C”

38
Q

DNApol 3

A

Elongates leading strand, growing f
Adds nucleotides onto the 3’ end, growing the strat from the 5’ towards 3’ like all of them.

5’ –> 3’ polymerase activity

3’ –> 5’ exonuclease proofreading activity

39
Q

DNA pol 1

A

The one that has 5’ –> 3’ exonuclease activity, so it can remove the RNA primers as it synthesizes.

Also has 5’ to 3’ polymerase activity and 3’ to 5’ exonuclease activity for proofreading.

40
Q

HIV gene Pol gene

A

All the genese needed to transcribe new viral RNA, Rting it, integrating it, and cleaving the prepeptide.

Reverse Transcriptase
\+
Integrase
\+
Protease
41
Q

HIV Gag gene

A

Core proteins and Nucleocapsid proteins

p24 and p7.

42
Q

HIV Env gene

A

Glycoproteins (envelope proteins)

Produces gp160, which is cleaved by viral protease in the Golgi to
gp120
gp41

43
Q

Times when gyndecomastia can be normal in males

A

Physiologic gynecomastia:
Newborns present in 70% of cases
Puberty peaks at ages 13-14 years
Elderly persons occurs between 50 an 80 years of age

44
Q

Wrinkles caused by

A

Decreased synthesis of elastin and collagen

decreased ECM turnover

45
Q

Idiopathic thrombocytopenic purpura

A

Autoantibodies against the gp2b3a receptor

46
Q

TTP

A

Autoantibodies against ADAMTS protein and accumulation of very large vWBF

47
Q

The 3 types of homocystinuria

A

Cystathione synthase deficiency:
- presents: increased homocysteine and methionine, and decreased cysteine, which needs to be supplemented, as well as B6

Decreased affinity of cystathionine synthase for B6 pyridoxal phosphate.
- presents same as cystathione synthase deficiency.
Supplement with lots of B6 and cysteine

Methionine synthase deficiency.

  • Low methionine, high homocysteine,
  • treatment methionine supplementation.

All of them present with excess homocysteine.

  • homocysteineuria
  • osteoporosis
  • marfanoid
  • lens subluxation
  • AMIs and Strokes
  • Kyphosis
  • Intellectual disability
48
Q

Cystinuria

A

Cystine is two cysteines connected by a disulfide bond.

Hereditary defect of the intestinal and renal BASIC amino acid transporter.
the COLA transporter:
Cystine
Ornithine
Lysine
Arginine.

Hexagonal cystine stones in the urine.

Treat with urinary alkalinization, with Acetazolamide or potassium citrate. And hydration.

If the urine is more basic, then these basic proteins are less likely to pick up protons and become charged being trapped in the lumen. Alkalinization lowers their concentration in the urine.

49
Q

Duchenne dystrophy

A

XLR
Caused by a FRAMESHIFT or nonsense mutations

The calf has pseudohypertrophy, but the weakness begins in the Pelvic Girdle muscles and the Ascends superiorly.

Death by DILATED CARDIOMYOPATHY

50
Q

Becker dystrophy

A

XLR

Caused by DELETIONS (non-frameshift deletions)

51
Q

Myotonic dystrophy type 1

A

C
T
G
repeat expansions in the DMPK gene. Dominant myotonic dystrophy.

Muscle atrophy plus CTG

  • Cataracts
  • Toupees
  • Gonadal atrophy
52
Q

Paclitaxel

A

a TAXANE type drug (tarzan)

Stabilizes microtubles preventing depolymerization
M phase specific cell killing.

Has a SERIOUS hypersensitivity reaction as a possible side effect.
ALL patients are required to be pre-treated with:
Dexamethasone - corticosteroid
Diphenhydramine - antihistamine
H2 blocker - cimetidine

53
Q

Vinca alkaloid drugs

A

Vincristine and Vinblastine

Bind to tubulin and inhibit its polymerization.
Also M phase specific killing.

54
Q

Centrilobular necrosis

A

liver congestion
Acetominophen poisoning
CCl4 poisoning.

-acetominophen and ccl4 are due to the highest concentrations of CYP being cental.

55
Q

Periportal necrosis

A

GVHD

Hepatitis

1 USMLE NOTES (6 decks)

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