First Aid 31-54 Flashcards by Mary Slome

Collects data from a group of people to assess frequency of a disease/related risk factors at one point in time

Cross-sectional study

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A study that assesses disease prevalence

Cross-sectional study

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Compares a group of people with disease to a group of people without disease; looks for prior exposure or risk factor

Case control study

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A study that measures odds ratio

Case-control study

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Compares a group of people with a given exposure or risk to a group of people without; can be prospective or historical

Cohort study

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A study that looks to see if exposure affects the likelihood of disease

Cohort study

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A study that measures relative risk

Cohort study

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Compares the frequency with which both momozygotic or both dizygotic twins develop the same disease

Twin concordance study

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Compares siblings raised by biological vs adoptive parents

Adoption study

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Phase I clinical trial

Small number of healthy volunteers;

Is it safe?

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Phase II clinical trial

Small number of patients with disease of interest;

Does it work?

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Phase III Clinical trial

Large number of patients randomly assigned either to treatment or placebo/best available treatment;

Is it as good or better?

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Phase IV clinical trial

Postmarketing surveillance of patients after treatment is approved;

Can it stay?

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PPV equation

TP/(TP + FP)

proportion of people with the disease who test positive

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NPV equation

TN/(TN + FN)

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PPV and NPV vary based on

disease prevalence

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Sensitivity equation

TP/(TP+FN)

the probability that all people with the disease will test positive

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High sensitivity test used in screening in diseases with

low prevalence

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Specificity equation

TN/(TN+FP)

Proportion of all people without the disease who test negative

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High specificity test used when

A sensitivity screening test was positive

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What is point A? B? C?

A = 100% sensitivity cutoff

B = practical compromise between sensitivity and specitificity

C = 100% specificity cutoff

**Lower B –> increase FP, lower FN –> increase sensitivity and NPV

Raise B –> increase FN, lower FP –> increase specificity and PPV

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new cases/# people at risk

Incidence

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of existing cases / population total

Prevalence

Prevalence is about the pre-test probability

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(a/c) / (b/d)

Odds ratio

Odds people with disease were exposed / odds the group without disease was exposed;

Case-control studies

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a/(a+b) / c/(c+d)

relative risk cohort studies risk of developing disease in exposed group divided by risk in unexposed group

When prevalence is low, OR is about equal to

a/(a+b) - c/(c+d)

Attributable risk; difference in risk between exposed and unexposed groups

The proportion of risk reduction attributable to the intervention as compared to the control

Relative risk reduction; 1-RR = 1- a/(a+b) / c/(c+d)

The difference in risk attributable to the intervention as compared to the control

Absolute risk reduction c/(c+d) - a/(a+b)

NNT

1/ARR

NNH

1/AR

An increase in precision leads to

An increase in statistical power = 1-ß The absense of random variation in a test

The absence of systematic error or bias in a test

Accuracy The trueness of a measurement

Sampling bias is an example of

Selection bias; Fix with randomization

Confounding bias

When a factor is related to both the disease and the outcome, but is not causal

Lead-time bias

Early detection is confused with increased survival

1 SD includes

68% 2 SDs --\> 95% 3 SDs --\> 99.7%

Give an example of bimodal distribution

Fast vs slow acetylators

Stating that there is an effect or difference when none exists

Type I error (alpha error); You "a"bserved a difference that did not exist

p is judged against a pretest alpha level. If p\<0.05 then

there is a less than 5% chance the study shows something that is not really there

alpha is the probability of

making a type I error

Beta is the probability of

making a type II error

Ways in increase the power of a study

increase sample size; increase expected effect size increase precision of measurement

The closer the absolute value of r is to +1, then

the stronger the linear correlation between the two variables; Positive r value --\> one variable up means other variable up and vice versa

Moro reflex disappears by

3 months

Rooting reflex disappears by

4 months

Palmar reflex disappears by

6 months

Babinski reflex disappears by

12 months

lifts head up by

1 month

rolls and sits by

6 months

crawls by

8 months

stands by

10 months

walks by

12-18 months

passes toy from hand to hand by

6 months

pincer grasp by

10 months

points to objects by

12 months

social smile by

2 months

stranger anxiety by

6 months

separation anxiety by

9 months

orients to mom/dad voice by

4 months

orients to name and gestures by

9 months

object permanence by

9 months

says mama and dada by

10 months

climbs stairs by

18 months

feeds self with fork and spoon by

20 months

kicks ball by

24 months

rapprochment - moves away from mom and then returns by

24 months

gender identity by

36 months

200 words and 2 word sentences by

age 2

rides a tricycle by

age 3

drawings, copies lines or circles by

age 4

hops on one foot by

age 4

uses buttons/zippers, grooms oneself by

age 5

comfortabily spends part of day away from mom by

age 3

cooperative play, has imaginary friends by

age 4

1000 words by

age 3

uses complete sentences with prepositions by

age 4; can tell detailed stories by age 4

Sensorineural hearing loss due to destruction (often high frequency) of hair cells at cochlear base (preserved low frequency hearing at apex)

Presbycusis change in elderly

If you are \<65 and on Medicare, what are the two possible reasons?

End stage renal disease or certain disabilities

Histones are rich in what amino acids?

Lysine, Arginine

Nucleosome made of

H2A, H2B, H3, H4 all x 2

H1 stabilizes

DNA wrapped around histone

Why methylate template strang cytosine and adenine?

During DNA replication, allows mismatch repair enzymes to identify the old strand (in prokaryotes)

DNA methylation at CpG islands has what effect?

Represses transcription CpG Methylation Makes DNA Mute

Histone methylation

Usually reversibly represses DNA transcription but can activate it in some cases (depending on location)

Histeone acetylation

Relaxes DNA coiling --\> allows for transcription

Base + deoxyribose (sugar)

Nucleoside

Base + deoxyribose + phosphate

Nucleotide

Purines

2 rings Adenine Guanine

Pyramidines

1 ring Cytosine Uracil (deaminated cytosine) Thymine

Amino acids necessary for purine synthesis

Glycine Aspartate Glutamine (and THF)

MOA Leflunomide and pathway it acts in

Inhibits Dihydroorate dehydrogenase Pathway: Pyrimidine base production

Pyrimidine base production requires

Aspartate

MOA and pathway for: Methotrexate, Trimethoprine, Pyrimethamine

Inhibit Dihydrofolate reductase Disrupt pryamidine synthesis reduce dTMP being made

MOA and Pathway 5-fluorouracil

Disrupts pyrmidine synthesis forms 5-F-dUMP inhibits thymidylate synthase --\> lowers dTMP

What drug disrupts both purine and pyramidine synthesis?

Hydroxyurea Inhibits ribonucelotide reductase

Orotic aciduria is a failure of what pathway

Pyrimidine synthesis pathway; can't make UMP from orotic acid

MOA and Pathway of 6-mercaptopurine

(and its prodrug azathioprine) inhibit de novo purine synthesis inhibit step from PRPP --\> IMP (inosine monophosphate)

MOA and Pathway for Mycophenolate and Ribavarin

Inhibit IMP (inosine monophosphate) dehydrogenase Inhibit step from IMP --\> GMP Purine synthesis pathway

Xanthine oxidase: Pathway, steps, inhibitors

Purine salvage pathway; Catalyzes hypoxanthine --\> xanthine and xanthine --\> uric acid Inhibited by Allopurinol, Febuxostat

Adenosine deaminase: Pathway, step, pathology

Purine salvage pathway; Catalyzes Adenosine --\> Deoxyadenosine; ADA deficiency major form of AR SCID --\> dATP leads to toxicity in lymphocytes

HGPRT: Pathway, step, pathology

Purine salvage pathway; Needed for both Hypoxanthine + PRPP --\> IMP and Guanine + PRPP --\> GMP; Deficiency is Lesch Nyan syndrome --\> hypoxanthine gets shunted to uric acid production (X-linked recessive)

Promotors and origins of replication are rich in what bases

Unwinds DNA template at replication fork

Helicase

Prevents unwound strands from re-annealing

single-stranded binding proteins

Create single or double-stranded breaks in helix to add or remove supercoils

DNA topoisomerases

What two drugs inhibit eukaryotic topoisomerase II?

Etoposide, Teniposide

What drugs inhibit prokaryotic topoisomerase II (DNA gyrase) and topoisomerase IV?

Fluoroquinolones

Primase makes an RNA primer on which ____ can initiate replication

DNA Pol III

DNA Pol III is found in

prokaryotes only

Catalyzes phosphodiester bonds between Okazaki fragments

DNA ligase

Telomerase is found

in eurkaryotes only; often disregulated in cancer cells --\> unlimited replication

Common silent mutation

Base pair change in 3rd position of codon (tRNA wobble)

Sickle cel disease, what mutation and what KIND of mutation?

glutamic acid --\> valine; Missense mutation - nucleotide substitution resulting in changed amino acid

Two examples of frameshift mutations

Duchenne MD; Tay-Sachs

When does nucleotide excision repair occur?

Nucleotide excision repair defective in

Xeroderma pigmentosum - cannot repair thymidine (pyramidine) dimers from forming with UV light exposure

Base-specific glycosylase removes altered base and creates AP site; AP endonuclease cleaves 5' site; Lyase cleaves 3' site; DNA polymerase-beta fills gap, DNA ligase seals

Base excision repair; Occurs throughout cell cycle; Important for repair of toxic or spontaneous deamination

Newly synthesized strand recognized, and mismatched nucleotides removed

Mismatch repair; predominantly occurs during G2 Defective in Lynch syndrome (hereditary nonpolyposis colorectal cancer)

Brings together 2 ends of DNA fragments to repair ds breaks

Nonhomologous end joining; Mutated in ataxia telangectasia and Fanconi anemia

Stop codons

UGA UAA UAG

Start codon for prokaryotes

AUG (same for eukaryotes) but codes for N-formylmethionine (fMET) \*\*fMET is chemotactic for neutrophils

First Aid 31-54 Flashcards

(122 cards)