Biostatitics - Review Flashcards
Recall bias
results from inaccurate recall of past exposure
- applies mostly to retrospective control studies
- people who have suffered adverse effects are more likely to recall risk factors than those who don’t
Referral bias
- ocurs when the case and control populations differ due to admission or referral pracrices
- example, study involving cancer risk performed at cancer research hospital may enroll cases referred all over the nation however, hospitalized control
Detection bias
refers to risk factor itself may itself may lead to intensive investigation and may increase probability of finding disease
- patients who smoke may undergo increased imaging due to smoking status
Lead time bias
occurs when screening test diagnoses a disease earlier than it would have appeared by natural history so time from diagnosis until death appears longer
- affected studies may not accurately reflect improvement in health
Allocation bias
results from how the treatment and control are assembled. May occur if subjects are assigned to study groups of clinical trial in a non-random fashion
Hawthorne effect
tendency of study population to affect outcome due to knowledge of being studies
Berkson’s bias
selecting hospitalized patients as control group
Pygmalion effect
describes researcher’s effect in the efficacy of treatment that can potentially affect outcome
Cystinuria
caused by defect in renal proximal tubules which result in decreased resorption of amino acid cysteine
- renal stones at young age
- hexagonal cystine crystals
Sodium cyanide nitroprusside tests
detects cystine’s sulfhydryl groups
- turns purple
Primary oocytes
- developed by 5th month of gestation
- arrested in PROPHASE of meiosis I
Secondary oocytes
- arrested in METAPHASE of meosis II prior to fertilization
Sx: Simultaneous development of stroke, foot/intestinal ischemia and renal infarction. Likely diagnosis
Embolic phenomena
- often caused by left atrial clots, left ventricular clots, valvular vegetations, and aortic sclerotic plaques
Sx: Signs of renal failure (increased creatinine) and toe gangrene/livedo reticularis. Likely diagnosis?
Atheroembolic renal disease
- cholesterol emboli obstructs renal arterioles
Sx: Urinary hestinancy, urgency, frequency, incomplete coiding, post-void leakage in men > 60 years old.
BPH
Prostate
found between pubic symphysis and anal canal
Common causes of impetigo
S. aureus and Group A Strep
Post-streptococcal glomerulonephritis
- follows pharyngitis or skin infection (impetigo)
Conditions caused by incomplete obliteration of processus vaginalis
Hydrocele
Indirect inguinal canal
Hydrocele
- due to incomplete obliteration of processus vaginalis
- occurs when there is connection between scrotum and abdominal cavity that allows for leakage of fluid
Secretory phase of menstrual cycle
- occurs between ovulation and menses
- progesterone released by corpus luteum causes uterine glands to coil and secrete mucus-rich secretions and plumps up endometrium
In follicular phase, what hormone mediates endometrial proliferation?
Estrogen
- glands appear straight and narrow (small lumens)
In secretory phase, what hormone mediates endometrial proliferation
Progesterone
- glands appear dilated and coiled (wide lumens)
Best way to visualize T. pallidum
Darkfield microscopy
