SIAD Exam #1

Social Inequality

the unequal opportunities and rewards for different social positions or statuses within a group or society

Social positions/statuses

religion, race, age, gender, sexual orientation

rewards

income, wealth, education, employment

burdens

unemployment, incarceration, substance abuse

poverty

to lack or be denied access to goods, services, and infrastructure necessary to sustain basic human capabilities

absolute poverty

having less than an objectively defined absolute minimum; does not change over time except for inflation

relative poverty

having less than others in society; changes with economic growth

US poverty threshold; Family of 4

$30,900

2023 national poverty rate

11.1%, about 37 million people

Race

socially constructed category rooted in the belief that there are fundamental differences among humans, associated with phenotype and ancestry

ethnicity

cultural values and norms that distinguish the members of a given group from others

structural racism

a system in which public policies, institutional, practices, cultural representations, etc. perpetuate racial group identity

Total world population in 2025

about 8.2 billion

US population in 2025

about 341 million

Inequality within countries

measured with Gini Index

Inequality between countries

gross national income (GNI) per capita

Extreme poverty

living on less than $2.15 per day

Total number of people living in extreme poverty in 2022

about 838 million; about 10.5% of global population

Sustainable development goals

Zero hunger, good health and well-being, clean water and sanitation

Health inequities

health differences that are closely linked with social, economical, and/or environmental disadvantage

health equity

the attainment of the highest level of health for all people by eliminating health inequities

social gradient in health

the correlation between socioeconomic status and health; at each level of socioeconomic status there is a difference in health

social determinants of health

conditions in the places where people are born, live, learn, work, and play that affect a wide range of health and quality of life risks and outcomes

Social inequality to disease

inadequate housing, poor sanitation, malnutrition

Disease to social inequality

medical costs, reduced ability to work/loss of wages, disease stigma/discrimination

social justice

the fair distribution of wealth, opportunities, and privileges within a society

epidemiology

the study of disease frequency, determinants of disease and other conditions, and the pattern and distribution of disease and other conditions in a population

public health

the science of protecting and improving the health of communities through education, promotion of healthy lifestyles, and research for disease and injury prevention

ten great health achievements

vaccination, motor-vehicle safety, safer workplaces, family planning, control of infectious diseases

social medicine

the social conditions and characteristics of patients, the social causes of illness, and contexts of medical care

population

a group of people who share a common characteristic

distribution

the frequency and pattern of health-related characteristics and events in a population

frequency

proportion of a population that is affected by a particular disease

incidence

the number of new disease cases reported in a population over a certain period of time

prevalence

the total number of individuals in a population that have a disease or health condition at some designated time

equation of prevalence

prevalence = incidence x duration of time an individual has the disease

determinants

any factor that can bring about a change in health

risk factors

activities or factors that increase an individual’s risk of developing a disease or health condition

epidemic

the occurrence of cases of an illness in a community or region which is in excess of the number of cases normally expected for that disease in that area at that time

pandemic

global epidemic

endemic

the usual presence of a disease in certain areas

morbidity

disease or injury

mortality

death

Disability Adjusted Life Years (DALYs)

number of healthy years of life lost to illness and injury and premature death

DALYs equation

DALY = premature death years + disability years

HIV

human immunodeficiency virus

virus

microscopic infectious agent that can replicate only within a living cell (therefore, an obligate intracellular parasite) consisting of DNA or RNA surround by a protein coat

AIDS

acquired immune deficiency syndrome

AIDS diagnosis

a person with HIV must have an AIDS defining condition OR have <200 CD4+ lymphocytes per microliter of blood

Transmission of HIV

by contact with body fluids from a person infected with HIV (blood, semen, vaginal fluid, breast milk)

Estimated prevalence of HIV/AIDS in people greater than 13 years old in US in 2022

about 1.2 million people (0.4%)

Estimated incidence of HIV infection in 2022

about 33,000 new cases

HIV major conclusions

MSM in the population most affected by transmission; blacks most affected by race; highest risk group is young black MSM

social determinants for HIV

poverty (more likely to exchange sex for goods, reduces access to healthcare), discrimination/stigma (reduces likelihood of testing/prevention/treatment, hiding sexual orientation increases risk to female sex partners), incarceration (disrupts sexual networks in community, decreases sex partners for women)

prevention for HIV

abstinence, being faithful, condoms, clean needles, use pre-exposure prophylaxis, take meds when positive

retrovirus

have genomes that consists of single-stranded RNA, which after infection, are reverse transcribed into double-stranded DNA which is then integrated into the hot cells chromosomal DNA

Viral RNA

2 copies of single stranded RNA (about 10,000 nt each); enclosed within a protein capsid; capsid enclosed by protein matrix; enclosed by phospholid bilayer envelope; contains viral glycoproteins of gp41/gp120

retroviruses encode 3 major proteins

Gag (group specific antigen), Pol (polymerase), Env (envelope)

polyproteins

large proteins cleaved by proteases (break peptide bonds) to produce two or more smaller proteins

Pol creates

protease, reverse transcriptase, integrase, gp120

gp120

protein that has sugar molecules covalently linked to it; interacts with CD4

reverse transcriptase

DNA polymerase that uses RNA as a template to make DNA

integrase

enzyme integrates DNA into host cell

HIV infection

starts with infection of macrophages (type of leukocyte); over time infects another leukocyte (helper T cells)

macrophages/helper T cells

carry CD4 protein on plasma membranes; CD4+ cells; receptors for HIV

1st step HIV life cycle

HIV binds to CD4 receptor and a co-receptor on the cell surface and enters the cell by fusing with the cell membrane; gp120 binds to CD4 receptor

HIV co-receptors

CCR5 for macrophages; CXCR4 for T cells; chemokine receptors

Chemokine receptors

proteins that regulate the immune system

fusion

HIV is taken into the cell; the viral envelope fuses with the cell’s plasma membrane

2nd step of HIV life cycle

Reverse transcriptase copies RNA genome into double stranded cDNA; viral RNA destroyed by RNase; ss cDNA is used as a template to synthesize a complementary DNA strand; results in dsDNA

3rd step of HIV life cycle

viral cDNA enters the nucleus and is integrated into cells chromosomal DNA

4th step of HIV life cycle

viral genes are transcribed and mRNAs are translated; mRNAs are translated to produce viral proteins

5th step of HIV life cycle

viral proteins are processed by proteases, viral particles assemble and bud from the cell; polyproteins are cleaved by proteases to form mature viral proteins; proteins assemble on the cell’s plasma membrane; enclose new viral genomic RNA molecules

budding

new viral particles are formed/released

pathogenesis of HIV

infection (symptoms gone after 2-4 weeks); acute stage (viral load is extremely high); strong immune response (8-10 years); AIDS (<200 CD4+ cells/uL blood)

CD4+ T cells

helper cells that stimulate other immune cells to produce antibodies and cytokines

cytokines

proteins that activate the immune system

HIV antibody and HIV antigen detection

tests for both presence of antibodies against HIV and for an HIV protein (p24) in blood; if positive, a confirmatory test to directly detect viral RNA is done

antibodies

proteins produced by certain immune system cells in response to a foreign substance

antigen

any substance that can provoke the immune system to produce antibodies

direct detection of viral genetic material (nucleic acid test)

uses non-PCR technique to amplify viral RNA from HIV present in the blood

known infection/under treatment for HIV

quantitative PCR used to measure concentration of virus in blood

eclipse period

limitation of HIV testing; typically 10-12 days during which no current test can detect a new infection

Treatment for HIV

no cure; antiretroviral therapy should start asap after diagnosis

nucleotides

nitrogenous base, pentose sugar, and phosphate

nucleosides

nitrogenous base and pentose sugar

DNA

polynucleotide linked by phosphodiester bonds; 5’-3’ polarity

DNA polymerase

enzyme that synthesizes chromosomal DNA; only add new nucleotides to 3’ OH group

Reverse transcriptase

special type of DNA polymerase that uses RNA instead of DNA as a template

nucleoside/nucleotide RT inhibitors

structural analogs of nucleotides required for DNA synthesis; azidothymidine

AZT

after entering a cell, phosphate groups are added to the 5’ carbon, converting to a nucleotide; competes with incorporation in ssDNA so nucleotides cannot be added; inhibits reverse transcriptase through chain termination

non-nucleoside RT inhibitors

block RT activity by binding at a site different than the site bound by NRTI; Efavirenz

combination therapy

use combinations of at least two different classes of drugs; commonly integrase inhibitor and two NRTIs

drug resistance arises because:

large number of viral particles; RT is highly error prone; high degree of genetic variation among viruses

mutation

a heritable (inherited) change in the genetic material; occur randomly with respect to location and time

induced mutations

mutations caused by mutagens; not relevant to HIV

spontaneous mutations

occur naturally and continually, and are the ultimate source of natural genetic variation; major source: replication errors

amino acid substitutions

alter the structure and function of the protein

phenotype

the physical characteristics of an organism

natural selection

the differential survival and reproduction of different phenotypes in a population