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First Aid 2017
| Term | Definition |
|---|---|
| Cross-Sectional Study | Study looking at one particular point in time Measures disease prevalence Can show risk factors without proving causality |
| Case-Control Study | Study comparing disease to no disease looking for risk factor Measures Odds ratio |
| Cohort Study | Study comparing group with and without certain exposure Measures relative risk |
| Phase I clinical trial | Small number of healthy volunteers |
| Phase II clinical trial | Small number of patients with disease of interest |
| Phase III clinical trial | Large number of patients randomly assigned either to the treatment under investigation or the best available treatment |
| Phase IV clinical trial | Postmarketing surveillance or patients after treatment is approved |
| Sensitivity | Proportion of people with disease who test positive = TP / (TP + FN) |
| Specificity | Proportion of all people without disease who test negative = TN / (TN+FP) |
| Positive predictive value | Proportion of positive test results that are really positive = TP / (TP+FP) |
| Negative predictive value | Proportion of negative test results that are really negative = TN / (TN+FP) |
| Incidence | new cases / people at risk |
| Prevalence | existing cases / number of people |
| Lowering cutoff point of a test | increases sensitivity and decreases specificity |
| Raising the cutoff point of a test | increases specificity and decreases sensitivity |
| Odds ratio | Odds that the group with the disease was exposed to a risk factor =ad/bc |
| Relative risk | Risk of developing disease in the exposed group / unexposed = [ a/(a+b) ] / [ c / (c+d) ] |
| Attributable risk | difference in risk between exposed and unexposed groups =[a / (a+b) } - [c / (c+d) ] |
| Relative risk reduction | proportion of risk attributable to an intervention = 1 - relative risk |
| absolute risk reduction | difference in risk attributable to an intervention - [c / (c+d) ] - [a / (a+b) ] |
| number needed to treat | number of patients who need to be treated for one patient to benefit = 1 / absolute risk reduction |
| number needed to harm | number of patients who need to be exposed to a risk factor for one patient to be harmed = 1/ absolute risk |
| precision | consistency and reproducibility |
| accuracy | trueness of test measurements |
| Selection bias | error in assigning subjects to a study group resulting in an unrepresentative sample (reduced by randomization) |
| Berkson bias | study population selected from unhealthy hospital |
| Recall bias | People with a disease remember more |
| Measurement bias | information is gathered in a systematically distorted manner |
| Procedure bias | Subjects in different groups are not treated the same |
| Observer-expectancy bias | Researcher expects certain outcome of treatment |
| Confounding bias | A factor is related to both the exposure and the outcome |
| Lead-time bias | early detection is confused with increased survival |
| Type I error | Stating that there is a difference when there is none |
| Type II error | Stating that there is no difference when there is one Power = 1 - type II error |
| t-test | Differences between the means of 2 groups |
| Analysis of variance | Differences between the means of 3 or more groups |
| Chi-squared | Differences between 2 or more percentages of categorical outcomes |
| Autonomy | Obligation to respect patients as individuals |
| Beneficence | Duty to act in the patient's best interest |
| Nonmaleficence | Do no harm |
| Patient is not adherent | Figure out why and see if they would change, don't force them or refer them |
| Patient desires unnecessary procedure | Understand why and address underlying concerns, don't refuse to see them or refer |
| Patient has difficulty taking medications | Provide written instructions, simply treatment regimen, teach back method |
| Family members ask about prognosis | Need patient's permission |
| Family member says don't tell patient | Figure out why, but tell them you have to |
| Patient is angry about long wait time | Acknowledge and apologize without explaining why |
| Invasive test performed on wrong patient | Ethically obligated to inform patients of mistakes |
| Treatment not covered by insurance | Don't limit or deny care |
| Developmental milestones in 1 year | Primitive reflexes disappear, sits, uses hands, smile, separation and stranger anxiety, orients to voice and name, object permanence, and speaking |
| Developmental milestones in 1-2 years | Walks, Stairs, stacks cubes, feeds self, kicks ball, plays with people |
| Developmental milestones in 3-5 years | rides tricycle, draws, increased dexterity, plays away from mother, tells stories |
| Changes in the elderly | Less REM, more suicide and fat, Worse vision, hearing, immunity, bladder control, renal, pulmonary, GI function, muscle mass |
| Heterochromatin | Condensed, darker on EM, inactive |
| Euchromatin | Less condensed, lighter on EM, active |
| DNA methylation | Template strands are methylated at cytosine and adenine Mehtylation at CpG islands represses transcription |
| Histone methylation | Reversibly represses DNA transcription (sometimes activates) |
| Histone acetylation | Relaxes DNA coiling allowing for transcription |
| Purines | Adenine, Guanine, 2 rings |
| Pyrimidines | Cytosine, Uracil, Thymidine 3 rings |
| Deamination of cytosine | uracil |
| G-C bond | Stronger than A-T bond |
| Leflunomide | Inhibits dihydroorate dehydrogenase which converts carbamoyl phosphate to orotic acid and uses aspartate |
| Orotic aciduria | Impaired conversion of orotic acid to UMP which uses PRPP |
| Methotrexate, Trimethoprim, Pyrimethamine | Inhibit dihydrofolate reductase decreasing deoxythymidine monophosphate conversion by thymidylate synthase in humans, bacteria, and protozoa. |
| 5-fluorouracil | Forms 5-F-dUMP which inhibits thymidylate synthase |
| 6-mercaptopurine (prodrug azathioprine) | Inhibits de novo purine synthesis |
| Mycophenolate and ribavirin | inhibit inosine monophosphate dehydrogenase which converts IMP to GMP |
| Hydroxyurea | inhibits ribonucleotide reductase which converts UDP into dUDP |
| Adenosine deaminase deficiency | Converts adenosine to inosine. Increased dATP causes toxicity in lymphocytes, causes autosomal recessive SCID |
| Lesch-Nyhan | Defective purine salvage due to absent HGPRT which converts hypoxanthine to IMP and guanine to GMP. Excess uric acid and PRPP. Intellectual disability, gout, self-mutilation |
| Unambiguous | each codon specifies only 1 amino acid |
| Degenerate/ redundant | most amino acids are coded by multiple codons |
| Non-overlapping | continuous sequence of bases |
| Origin of replication | Where DNA replication begins |
| Replication fork | Y shaped region along DNA template where leading and lagging strands are synthesized |
| Helicase | Unwinds DNA at replication fork |
| Single-stranded binding proteins | Prevent strands from re-annealing |
| DNA topoisomerase | Creates a single or double-stranded break in the helix to add or remove supercoils |
| Primase | Makes RNA primer on which DNA polymerase III can initiate replication |
| DNA polymerase III | Prokayotic elongates leading strand elongates lagging strand until reaches primer of preceding fragment 3'-5' exonuclease (proofreading) |
| DNA polymerase I | Prokaryotic Degrades RNA primer (5'-3' exonuclease) |
| DNA ligase | Catalyzes phosphodiester bonds within a DNA strand |
| Telomerase | Eukaryotic RNA-dependent DNA polymerase that adds DNA to the 3' end to avoid loss of genetic material with every duplication |
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