Bioengineering

1
Bioengineering World Health

• Lecture Three

2
Review of Lecture Two

• Developing world
• Perinatal conditions
• Lower respiratory infections
• Diarrheal diseases
• Malaria
• Developed world
• Perinatal conditions
• Congenital anomalies
• Lower respiratory infections
• Unintentional injuries

3
Leading Causes of Mortality Ages 15-44

• Developing World
• HIV/AIDS
• Unintentional injuries
• Cardiovascular diseases
• Tuberculosis
• Developed World
• Unintentional injuries
• Cardiovascular diseases
• Cancer
• Self-inflicted injuries

4
Burden of HIV/AIDS

• Worldwide
• 40 million people are living with HIV/AIDS
• 20 million people have been killed by the disease
• 2003
• 3 million deaths
• 5 million new HIV infections
• 2/3 of those with AIDS are in Africa
• 1 in 12 African adults has HIV/ AIDS

5
AIDS has Reduced Life Expectancy
6
Burden of HIV/AIDS

• United States
• 0.8-1.2 million people have HIV/AIDS (prevalence)
• 30,000-40,000 new HIV infections per year
  (incidence)
• Annual cost to treat 15 billion

7
Clinical Course of HIV/AIDS

• HIV Infection (Human Immunodeficiency Virus)
• Spread by sexual contact with infected person or
  sharing needles with infected person or by
  transmission from mother to child
• Starts with an acute infection (flu like
  symptoms)
• Destroys a type of cell called CD4 lymphocytes
• These cells are a critical component of the
  immune system the bodys way to fight infection
• Latent Period
• After the initial flu like symptoms, adults may
  not experience any symptoms for 10 years. People
  can still spread the disease during the latent
  period.
• AIDS (Acquired Immune Deficiency Syndrome)
• Following the latent period, the number of CD4
  lymphocytes will reach a critically low level,
  causing AIDS.

8
Clinical Course of HIV/AIDS
Flu like symptoms
Little or no symptoms, still infectious
AIDS
9
What is AIDS?

• AIDS
• Immunologic dysregulation
• innapropriate response of immune system
• Opportunistic infections and cancers
• Infections and cancers that would not occur in a
  person with a normally functioning immune system
• Average patient with AIDS dies in 1-3 years
• Within 10 years of infection (without treatment)
• 50 of HIV patients develop AIDS
• 40 develop illness associated with HIV
• 5-10 remain asymptomatic

10
Pathophysiology of HIV/AIDS
http//health.howstuffworks.com/aids3.htm
11
Pathophysiology of HIV/AIDS
http//www.roche.com/pages/facets/4/hiv_life_cycle
2.jpg
The HIV virus enters cells (CD4 lymphocytes)
that are a critical component of the bodys
immune system. Once inside, the virus takes over
the cells internal machinery to make copies of
itself, destroying the cell in the process.
12
HAART Treatments for HIV/AIDS

• Highly Active Antiretroviral Therapy (HAART)
• Combination of three or more drugs
• HIV can rapidly mutate to quickly develop
  resistance to a single drug
• Resistance develops much more slowly to drug
  combinations
• Goal of HAART
• Reduce viral levels to
• undetectable levels
• Has reduced death rate
• in US and Europe by 80

Before and after HAART Treatment
13
http//www.npr.org/templates/story/story.php?story
Id4724368
14
Unintentional Injuries

• More than 1.25 million people aged 15-44 die as a
  result of unintentional injuries each year
• Major cause of disability
• Leading cause is road traffic injuries
• 500,000 deaths per year in his age group
• 90 of these deaths occur in developing countries

15
US Burden of Disease Road Accidents

• Rates declining steadily
• Leading cause of potential years of life lost
• 2004
• 42,636 Americans killed
• 2,788,000 Americans injured
• Fatal accident rates gt4X higher for males than
  for females
• Motorcycles 40X higher death rate per mile
  traveled
• 39 of fatalities related to alcohol use

16
Prevention Road Accidents

• Legislation
• Speed
• Seat belts, Car seats,
• Air Bags
• Alcohol use
• Motorcycle helmets
• Engineering
• Restraints
• Safety standards
• Education
• Seat belts, Car seats, Air Bags
• Alcohol use

Map of US motorcycle helmet Laws http//www.ironho
rsehelmets.com/laws.htm
http//www.usatoday.com/tech/columnist/edwardbaig/
2005-09-22-high-tech-gear_x.htm
17
Accident Physics

• Newtons 2nd Law
• F m a
• a initial velocity/time to come to rest
• In a crash
• Car velocity slows to zero in a very short time,
  so does the velocity of your body
• Generates large forces
• How can we reduce these forces?
• Reduce initial velocity of impact
• Extend time that it takes passengers to come to
  rest

18
Reducing Initial Velocity

• Excessive speed contributes to
• 30 of deaths in developed countries
• 50 of deaths in developing countries

19
Slowed Driver Reaction Time

• When drivers anticipate a crash, they have time
  to brake and reduce initial velocity
• Factors which slow driver reaction time
• Alcohol use
• Cell phone use
• Poor visibility

20
Alcohol Use

• Alcohol impaired drivers have 17X increased risk
  of being in fatal crash
• Alcohol use increases risk more in younger drivers

21
Alcohol Related Deaths
Video Clip included on teacher resource CD
22
Mobile Phone Use

• At any given daylight moment in US
• 10 of drivers are using a cell phone
• Cell phone use
• Increases driver reaction time by 0.5-1.5
  sections
• Risk of crash is 4X higher when using a mobile
  phone
• Same as driving with a BAC of 0.09 g/ dl
• 3 states have banned use of hand held phones
  while driving

23
Extending Time to Come to Rest

• Crumple zones
• Allow passengers additional time to decelerate
• Seat belts
• Keep occupants in the passenger compartment
• Stretch during impact
• Reduce risk of death in crash by 40-60
• http//www.regentsprep.org/Regents/physics/phys01/
  accident/nobelt.htm
• http//www.regentsprep.org/Regents/physics/phys01/
  accident/withbelt.htm
• Air bags
• When combined with seat belts, reduce risk of
  serious and fatal injuries by 40-65
• http//www.nhtsa.dot.gov/staticfiles/DOT/NHTSA/Com
  munication2020Consumer20Information/Multimedia
  /Associated20Files/crashdum2.ram
• http//www.accidentreconstruction.com/movies/5thpe
  r.mov
• Child restraints
• Reduce risk of infant death by 71 and toddler
  death by 54
• http//www.nhtsa.dot.gov/staticfiles/DOT/NHTSA/Com
  munication2020Consumer20Information/Multimedia
  /Associated20Files/crashdum3.ram

24
Helmet Laws
25
Cardiovascular Diseases

• 768,000 people aged 15-44 die as a result of
  cardiovascular disease every year
• Most common causes
• Ischemic heart disease (286,000 deaths)
• Cerebrovascular disease (159,000 deaths)

26
Ischemic Heart Disease Epidemiology

• United States
• 11 million people have coronary artery disease
  (hardening and narrowing of arteries)
• Causes more deaths, disability and economic cost
  than any other illness
• Risk factors
• Positive family history
• Diabetes
• Hyperlipidemia (High Cholesterol)
• Hypertension (High Blood Pressure)
• Smoking

27
Ischemic Heart Disease Pathogenesis

• Atherosclerosis
• Hardening and narrowing of the arteries due to
  build up of plaque.
• When the coronary arteries become narrowed, the
  supply of oxygen and nutrients to the heart is
  restricted. This damages the heart tissue.

28
Ischemic Heart Disease Diagnosis

• Usually made by history
• Physical exam may reveal other disorders
• High Cholesterol
• High Blood Pressure
• Diabetes
• Testing
• EKG
• Stress Testing
• monitoring the heart during exercise
• Coronary arteriography
• X-ray imaging of arteries

http//www.chadwickmedical.com/svc_electrocardio.h
tm
29
Ischemic Heart Disease Treatment

• Medical management
• Drugs
• CABG (Coronary Artery Bypass Graft)
• PTCA (Percutaneous Transluminal Coronary
  Angioplasty)
• More on these in unit 2!

30
Cerebrovascular Disease Stroke

• Third leading cause of death in the US
• Causes of stroke
• Blood vessel supplying the brain is blocked
• Thrombosis (clot in vessel)
• Embolism (clot breaks off and lodges in blood
  vessel in brain)
• Vasoconstriction or spasm
• Venous collapse

31
Cerebrovascular Disease Diagnosis
CT image pointing to areas of brain damage due to
stroke.

• History
• Exam
• Imaging
• CT Scan
• Computed Tomography Scan
• MRI
• Magnetic Resonance Imaging
• CT/MR Angiography
• Angiography refers to an image of the blood
  vessels created using MRI or CT

MRI image of brain following stroke.
http//www.theuniversityhospital.com/stroke/inhosp
ital.htm
MR Angiography of brain.
http//brighamrad.harvard.edu/Cases/bwh/hcache/93/
step-2.html
32
Cerebrovascular Disease Treatment

• Thrombolysis
• Break up blood clot
• Rehabilitation
• Experimental Treatments
• Angioplasty
• Heparin and Coumadin
• Blood Thinners
• Aspirin

At right X-ray image showing before and after
treatment
33
Tuberculosis

• 600,000 people ages 15-44 die each year from TB
• 2003
• 8.8 million new cases
• Growing 1/year
• 1.5 million deaths
• 98 of deaths occur in developing world
• Estimated that TB will kill 35 million people in
  next 20 years if situation does not change

34
Tuberculosis

• Bacterial infection of the lungs caused by
  mycobacterium tuberculosis
• Drugs which cure TB were discovered in 1940s
• If untreated, results in death in 5 years in half
  of all cases

Image of mycobacterium tuberculosis (tubercle
bacillus) http//www.nature.com/nature/journal/v43
4/n7034/full/434709a.html
35
(No Transcript)
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Tuberculosis

• 1/3 of worlds population is infected with TB
• Not all have active TB
• Most have latent TB - Immune system has walled
  off bacilli with waxy coat
• 5-10 of people with normal immune systems will
  go on to develop active TB
• Higher in people with compromised immune systems
  (10X higher in people with AIDS)
• TB is leading cause of death among people with
  HIV/AIDS
• http//www.npr.org/rundowns/segment.php?wfId15206
  99

37
Tuberculosis

• Symptoms
• Fever
• Night sweats
• Weight loss
• Weakness
• Coughs (productive with bloody sputum)
• Airborne transmission
• Left untreated, one person with active TB can
  infect 10-15 people each year

38
Tuberculosis Diagnosis

• Skin test
• Serum test
• CXR (Chest X-Ray)
• Shows nodules in active TB

39
Tuberculosis Treatment

• Latent TB
• Treated with isoniazid (antibiotic) , prevents
  development of active TB
• Active TB
• Can almost always be cured by taking several
  antibiotics in combination
• Stay home for several weeks while contagious
• Take drugs for 6 months

40
Tuberculosis

• Resistant TB
• Bacteria can develop resistance to drugs
• Can develop if patients do not take all medicine
• Growing problem
• 425,000 new cases per year
• In Russia and China, 14 of new cases are
  resistant
• Must be treated with special medicines
• Poorly supervised Treatment is worse than no
  Treatment

41
Fighting Resistance Directly Observed Therapy,
Short-course (DOTS)

• A health care worker watches and helps as the
  patient swallows anti-TB medicines in his/her
  presence.
• DOTS shifts responsibility for cure from patient
  to health care system
• Requires political commitment, accurate
  diagnosis, quality drugs, observation, follow up
• DOTS works well in many developing countries

42
Overlapping Epidemics

• Malaria and HIV
• For people with HIV, especially pregnant women,
  episodes of acute malaria are complicated and
  more serious.
• TB and HIV
• TB is the leading killer of people with HIV
• In Africa, half of all TB cases are associated
  with HIV.

43
Cancer

• 580,000 people aged 15-44 die every year due to
  cancer
• Cancer is a group of diseases characterized by
  uncontrolled cell growth
• Cancer cells usually form a tumor
• Cancer cells can spread from tumor to other sites
  in the body (metastasis)

44
2004 Estimated US Cancer Deaths
Men290,890
Women272,810
25 Lung bronchus 15 Breast 10 Colon
rectum 6 Ovary 6 Pancreas 4 Leukemia
3 Non-Hodgkin lymphoma 3 Uterine
corpus 2 Multiple myeloma 2 Brain/ONS 24
All other sites
Lung bronchus 32 Prostate 10 Colon
rectum 10 Pancreas 5 Leukemia 5 Non-Hodgkin 4
lymphoma Esophagus 4 Liver intrahepatic 3bil
e duct Urinary bladder 3 Kidney 3 All other
sites 21
ONSOther nervous system. Source American Cancer
Society, 2004.
45
Cancer

• 2nd leading cause of death in US
• 1 of every 4 deaths is from cancer
• 5-year survival rate 59
• Annual costs 107 billion

46
What is Cancer?

• Tumor
• Abnormal mass of tissue
• Growth exceeds that of normal tissue
• Purposeless and preys on host
• Caused by a single cell that has incurred genetic
  damage
• Types of Tumors
• Benign (not harmful)
• Malignant (harmful)
• Only malignant tumors can spread (Metastasize)

47
Microscopic Appearance
48
Biology of Tumor Growth

• Natural history of most cancers has 4 phases
• Malignant transformation in target cell
• Growth of transformed cells
• Local invasion
• Distant metastases

49
Importance of Cancer Screening

• 90 of cancer deaths are due to metastasis.

50
Burden of Self-Inflicted Injuries

• 480,000 people aged 15-44 take their own lives
  each year
• Highest rate of completed suicides
• Men gt65 years old
• Highest rate of attempted suicides
• Men and women ages 20-24

51
Risk Factors Associated with Suicide

• Psychiatric illness
• Affective, substance abuse, personality, other
  mental disorders
• Other risk factors
• Social adjustment problems
• Serious medical illness
• Living alone
• Recent bereavement
• Personal history of suicide attempt or completion
• Divorce or separation
• Unemployment

52
Screening and Prevention

• 50-66 of all suicide victims visit physician lt1
  month before event
• 10-40 in the preceding week
• Hard to identify who is at risk
• Direct questioning has low yield
• General questions about sleep disturbance,
  depressed mood, guilt and hopelessness
• Survey instruments arent good at predicting what
  will happen

53
Summary of Lecture Two

• Developing countries
• Leading causes of mortality ages 15-44
• Developing world
• HIV/AIDS
• Road Accidents
• Interpersonal violence
• Developed world
• Road accidents
• Self-inflicted injuries
• Interpersonal violence

54
Summary of Lecture 3

• Developing World
• HIV/AIDS
• Unintentional injuries
• Cardiovascular diseases
• Tuberculosis
• Developed World
• Unintentional injuries
• Cardiovascular diseases
• Cancer
• Self-inflicted injuries