Medical Interventions: Unit 1

What is the difference between cycle sequencing and PCR?

• PCR makes multiple identical copies and CS makes strands of different lengths

• CS is diagnostic; PCR just amplifies DNA

What does an ELISA do?

uses antibodies to detect proteins in a patient sample

What is the purpose of a constant region on an antibody?

To distinguish between self and foreign invaders.

What is the purpose of a variable region on an antibody?

To bind with a specific antigen.

Why must antibodies from 2 different organisms be used?

So that they recognize each other as non-self and bind to each other.

B-lactams: mechanism of action

Target transpeptidase which affects cell wall synthesis →makes bacterial defenses weaker

Tetracyclines: mechanism of action

Inhibit protein synthesis by inhibiting the 30s ribosome unit

Fluoroquinolones: mechanism of action

Inhibit topoisomerase (aka DNA gyrase) which inhibits DNA/RNA synthesis

Sulfa antibiotics/sulfonamids": mechanism of action

inhibit folate pathway (folate is a precursor to important nucleotides)

What are methods of antibiotic resistance?

• Mutation

• Destruction or inactivation: bacteria releases enzymes that degrade the antibiotic before it can do its job

• Efflux: the antibiotic enters the bacteria through a porin and is pumped out of the bacteria by an efflux pump

Methods of bacterial genetic transfer?

Conjugation

• One-way transfer of DNA (plasmid) through direct cellular contact (bacteria form a pilus (tube) to connect)

Transformation

• Uptake and expression of foreign DNA (EX: when one bacteria dies and spills its contents allowing another bacteria to uptake it)

Transduction

• Transfer of genetic material through a vector (bacteriophages, bacterial viruses, infect bacteria cells and use the as a host to replicate. Sometimes bacterial DNA is incorporated into the viral DNA and when the virus goes on to infect another bacteria, it takes the bacterial DNA with it)

Frequent waves →high pitched sound

Infrequent waves →low pitched sound

Tall waves →loud sound

Short waves →quiet sound

Structures in the outer ear

Pinna: outer, visible part of ear that gathers sound waves

External auditory canal: connects pinna to eardrum

Structures of the middle ear

Tympanic membrane/eardrum

Ossicles (Malleus, incus, stapes): tiny bones that transmit soundwaves

Eustachian tube: connects middle ear to the back of the nose and throat; equalizes pressure in ear

Also contains small muscles and tendons

Structures of the inner ear

Cochlea: when sounds enter they vibrate tiny hairs that send signals

Vestibular system

• semicircular canals: 3 looped tubes filled with fluid; helps with balance by telling our brain when we move head or change positions

Damage to the inner ear can cause hearing/balance problems

Pathway of sound in the ear

Auditory canal →Tympanic membrane (vibrates) →Ossicles →oval window (in cochlea) →Perilymph (also in cochlea; contain hairs [stereocilia] that send impulse to the brain)

Pathway of sound in ear: explain steps

1. Sound enters the auditory canal and causes the tympanic membrane to vibrate

2. Vibration of the eardrum causes the ossicles to move back and forth

3. The stapes movement against the oval window causes movement in the fluid that fills the cochlea

4. Movement of the fluid causes the stereocilia to move and send an impulse along the auditory nerve

5. The brain translates the impulse into sound

Label

Label

Conductive hearing loss

• Mechanical failure

• Something isn’t passing vibrations properly

• Usually in the middle ear

Sensorineural hearing loss

• issue with the inner ear

• could be and issue with the auditory nerve or cochlear stimulation

Live attenuated vaccines: Description and example

Inactivated or killed vaccines: Description and example

Toxoid vaccines: Description and example

Subunit vaccines: Description and example

Conjugate vaccines: Description and example

Qualities of a vaccine

Intradermal vs subcutaneous

Intradermal 

• superficial/shallow

• injection into the dermis (first layer of skin)

Subcutaneous

• Deep

• injection under all layers of skin

Live attenuated: steps

1. Grow virus strain in a tissue culture (must be colder than human body)

2. Fill syringe

Killed vaccine: steps

1. Grow new viruses

2. Isolate viruses

3. Kill viruses (heat, radiation, chemicals)

4. Fill syringe

Toxoid vaccines: steps

1. Copy virus in a growth medium

2. Isolate toxin with a purifier

3. Neutralize toxins (aluminum salts, formaldehyde)

4. Add an adjuvant to help it produce an immune response

Subunit vaccines: steps

1. pull out a segment of viral dna

2. Add to the DNA of a yeast cell

3. Use purifier to isolated the antigen produced by the yeast cells

Naked DNA vaccine: steps

1. copy viral gene with PCR

2. combine viral gene with vectors

3. Add bacteria to vectors so the bacteria can replicate

4. use the purifier to separate the altered vectors and bacteria

Similar pathogen vaccine: steps

1. collect a similar virus and isolate with purifier 

2. Fill syringe 

Recombinant DNA

a DNA molecule with segments from different sources

B-cells function

create antibodies

T-cells function

activated by antibodies, destroy pathogens

Helper-T function

can activate B-cells, macrophages, and others

how can you determine conductive hearing loss from a graph?

The bone conduction is at least 10db higher than air.