Chapter 15

NATURE AND NURTURE

You Started as One Cell: Stem cells

Nature/Nurture• Genetics is potential (Nature)

• Environment acts on this potential (Nurture)

• Forks in the road of Development

Preparing To Live On You Own: The HPA Axis

• Breathing

• Gluconeogenesis

• Epigenetics and development (Fetal programming

• Thrifty metabolism

Postnatal Development

• Organization of the nervous system

• Your brain is learning how to control your body

• Growth

• Puberty

Genetics

• Dominant

• Recessive

• Co-dominant• Also X-linked• Inherited probabilities

• Diabetes

• Heart disease

• cancer

Aging

• Hayflick Limit

• Other– Oxidative stress– Accumulated damage– Calorie restriction???

Healthcare: Manipulating Human Function

• Prevention, diagnosis, and treatment

• Medicine is becoming Drugs.

• Individualized medicine?

How Drugs are Prescribed

Drugs

• Alter relationships between molecules

• Alter balance

• Do not create anything new

Taking Drugs

Modes of Administration

• Topical (patch)

• Subcutaneous

• Oral

• Intra-peritoneal (I.P)

• Intra-muscular (I.M)

• Intra-venous (I.V)

The Body Acts on Drugs

Can Change the drug into another drug

Can detoxify the drug

Timing is important

• When a drug is taken is important– Resistance– Tolerance /dependence– etc

Removal of Drugs

• Liver

• Kidney

• Digestive system

Drug Development

• Natural compounds

• Synthetic compounds

• Screening

• Goal: safe and effective

Preclinical

• Chemical Characterization

• Cell culture

• Several Animal species– LD50 How much of the drug kills one-half of

the animals– distribution

Clinical Phase I

• Requires FDA approval

• Healthy volunteers

• Double blind: drug or placebo

• Side effects and toxicities

Clinical Phase II

• Requires FDA approval

• Healthy volunteers (safety)

• Some sick people (effective)

• Longer term treatment

Clinical Phase III

• Requires FDA approval

• Large scale clinical with patients

• Define “Safe” and “Effective”

• Risk vs Benefit

Clinical Phase IV

• Requires FDA approval

• On probation

• On the market

• Being tested on the public

The Assessment

Informed Consent