USMLE STEP 3 HIGH YIELD FACTS 2 EXAM Q&A.

What protein is most likely involved in the transport process leading to disease recurrence of Herpes? Kinesin = Anterograde transport of virus = motor protein that moves intracellular cargo (organelles, viral particles) away from nucleus, down axon, & toward nerve terminal - powered by ATP hydrolysis - guided by microtubule filaments Microtubular motor protein that participates in retrograde axonal transport (moving organelles toward nucleus). Establishes latent phase following primary HSV infection. Dynein Intermediate filament expressed in mesenchymal cells. Vimentin - secures organelles inside cytosol - resistance to mechanical stress Tendency of study subjects to change their behavior as a result of their awareness that they are being studied. Hawthorne effect (observer effect) Selection bias created by choosing hospitalized patients as control group. Berkson's bias Patient homozygous for apolipoprotein E-4 allele likely to suffer from Alzheimer dementia Early-onset Alzheimer disease associated with 3 gene mutations APP = chromosome 21 presenilin 1 presenilin 2 Cells that mediate hypersensitivity reaction of Candida extract skin reaction T-lymphocytes Delayed-type HS reaction (DTH) - contact dermatitis, granulomatous inflammation, tuberculin skin test - mediated by T-lymphocytes = 1-2 days following antigen exposure why you wait 48-72 hours for annual PPD test to be read! 6-year-old boy evaluated for recurrent infections & failure to thrive. He has been hospitalized for pneumococcal pneumonia twice & has had 5 episodes of otitis media, requiring placement of tympanosotomy tubes. The patient also has a history of prolonged diarrhea caused by Cryptosporidium parvum. Physical exam shows large tonsils, palpable lymph nodes, & hepatosplenomegaly. Further evaluation shows that the patient has defective signaling between CD4+ T cells & B lymphocytes. What immunoglobulins likely has the highest serum concentration in this patient? IgM Hyperimmunoglobulin M syndrome - defect in class switching in B lymphocytes - defective CD40L on Th cells -- class switching defect - high IgM - low IgG, IgA, IgE - recurrent sinopulmonary, GI, & opportunistic infections (Pneumocystis, Cryptosporidium) Bladder functioning of patients with multiple sclerosis Bladder hypertonia via urodynamic studies - develop spastic bladder few weeks after developing acute lesion of spinal cord - increased urinary frequency & urge incontinence Most common cause of Candida vaginitis Antibiotic use via reduction of lactobacilli population -- facilitates Candida overgrowth Key NTs involved in pathophysiology of ADHD NE & DA - stimulant drugs (methylphenidate & amphetamineds) = first-line drug treatments for school-aged children with ADHD Causes of Right shift in oxygen-Hb dissociation curve ACE BATs right handed Acid CO2 Exercise 2,3-BPG Altitude Temperature Anemia - can cause lactic acido