Transcript English - 3-Medicine%28mpz%20edit%29

III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.1. Pain and Inflammation Management
Morphine
Used from the early 1800s to decrease the sensation of
pain, morphine was extracted from raw opium. The
Hungarian pharmacist Janos Kabay revolutionized
morphine production in the 1920s by extracting it not only
from the immature poppy-head but from the dry poppystraw. It was studied in 1923 to determine its chemical
structure in an effort to synthesize a potent analgesic free
from undesirable properties such as addiction and
respiratory depression. Understanding how the naturallyoccurring extract worked on the human body allowed a
synthetic version of morphine to be developed and
subsequent safer drugs to be created, such as nalorphine
and naloxone in 1961.
Acetylsalicylic
acid
The thomb of Janos
Kabay in Budapest,
Hungary
Aspirin
In 1890, salicylic acid was being manufactured as a cheap
and effective inflammation reliever for rheumatoid arthritis,
despite its unpleasant side effects (nausea, gastric catarrh).
Acetylsalicylic acid (or aspirin) was synthesized in 1897 by
the German chemist Felix Hoffmann at Bayer and tested
pharmacologically by Heinrich Dreser. Production started in
1899 and the first pills were sold in 1900. Aspirin soon
became popular because it had far fewer side-effects than
salicylic acid. Aspirin, the first medicine to be produced at
and industrial level, is still manufactured in large quantities
today. Aspirin was consumed mainly as an anti-headache
drug until the mid-eighties, when its beneficial effects in
preventing heart attacks were discovered.
Cortisone
In the 1940s, studies of the adrenal gland cortex
identified that certain naturally-occurring hormones (also
called steroids) as having anti-inflammatory properties.
First isolated from its natural source in 1936, cortisone
was later synthesized by the American Lewis Hastings
Sarett in 1948. It was already being commercially
manufactured in the next year due to its miraculous
affect on rheumatoid arthritis. Subsequent clinical
studies showed that it did not cure arthritis, and
triggered serious side effects, but enjoyed additional
uses in asthma and allergy treatments. Further studies
of steroid synthesis led to the creation of prednisone,
prednisolone, and dexamethasone as better antiinflammatory agents with reduced side effects.
Lewis Hastings Sarett
Deformity induced by
joint inflammation
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.2. Psychotherapeutic Agents
Chlorpromazine
Chlorpromazine (Thorazine, Hibernal) was first used to
treat schizophrenia in 1954, after its original creation as
an antihistamine anti-allergic. This new therapy proved
itself dramatically effective and heralded the modern era
of antipsychotic therapy. Controlling mental illness
through medication soon supplanted earlier treatment
methods, such as electroshock, insulin shock, prefrontal
lobotomy (a surgical treatment disconnecting prefrontal
hemispheres), and helped to decrease the rate of
institutionalization worldwide. Later research shed light
on the pharmacological mechanism of chlorpromazine
and served as a basis for the development of many other
anti-psychotic drugs, such as Haloperidol and
Olanzapine.
Pictures from the film: One Flew Over the
Cuckoo’s Nest (1975), which portrays the
disastrous effects of mental illness
The onset of depression
following labour
Tricyclic antidepressants
In 1958, a clinical study of Imipramine, a drug which was
originally developed as an antipsychotic, revealed its
antidepressant properties. It functions therapeutically by
affecting the activity of neurotransmitters (stimulus
transmitting agents) in the brain. The many subsequent
drugs that were developed in this class became
collectively known as `tricyclic’ antidepressants. Tricyclic
antidepressants soon become the standard of therapy for
this dehabilitating disease.
Benzodiazepines
In 1959, Chlordiazepoxide (Librium) launched a potent
new class of anti-anxiety agents, the benzodiazepines.
This drug and its subsequent derivatives rapidly replaced
barbiturates and Meprobamate, an earlier, moderately
successful anxiolytic agent discovered in 1950, and are
considered to be some of the most successful drugs of
this era. The highly tolerable and safe benzodiazepines
also proved successful as hypnotic agents, muscle
relaxants, and as a treatment for epilepsy.
Neurotransmitters in the
brain
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.3. Hormones and Hormone Regulators
Insulin
Insulin, a protein hormone produced by special cells of the
pancreas, controls the level of blood sugar (glucose) in the body.
Lack of insulin leads to the development of type 1 diabetes, a
disease that was considered fatal until the early 1920s. Two
young Canadian doctors, Frederick Banting and Charles H.
Best, isolated and purified a new injectable extract from bovine
pancreas in 1921. Their first patient was a dying 14-year-old boy,
who was released from the hospital after a few weeks. Insulin
was manufactured from bovine pancreas by Eli Lilly and
Company in 1922. The first insulin engineered from human
sources using recombinant DNA technology was produced in
1982.
Frederick Banting and
Charles H. Best in a
painting
Testosterone
Testosterone is responsible for the development of the male
sexual organs and secondary sexual characteristics. It is a
steroid hormone, structurally similar to cholesterol. Testosterone
was first synthesized from cholesterol in 1935 to treat hormone
deficiency diseases. Testosterone can be manufactured by
chemical and microbiological modification of readily available
naturally-occurring materials.
Progestins, estrogens and oral contraceptives
In the 1930s, two female hormones were isolated and produced
from natural sources, the urine of pregnant mares and the Mexican
sweet root. Progestins (progesterone, luteal hormone) were
discovered to maintain gestation, and estrogens (follicular
hormones) were understood to affect menstrual cycles. In the 1950s,
synthetic versions of these hormones were produced and their
effects on human conception and pregnancy were studied. Their
excellent contraceptive qualities led to the development of oral
contraceptives (birth control pills) for women. Enovid, marketed in
the USA in 1960, was the first birth control pill to contain a mixture of
estrogens and progestins for maximum effectiveness.
III.4. Gastro-intestinal Agents
Evolution of ulcer therapy
In 1972, James Black, a Scottish pharmacologist, and his colleagues
at Smith, Kline & French shed light on the basis of surplus acid
secretion in the stomach. This type of pharmaceutical research is now
known as “rational drug design”. By 1976, they developed the drug
Cimetidine (Tagamet) which inhibits gastric acid secretion with minimal
side-effects, and its widespread use for gastric ulcers dramatically
decreased the need for surgery. Tagamet soon became medicine’s
most frequently prescribed drug.
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.5. Medical Testing and Disease Diagnostics
Medical imaging technologies
Devices such as x-ray machines and MRI (magnetic resonance imaging)
scanners, revolutionary at the time of their discovery, are now a routine
part of medical diagnosis and care. Wilhelm Konrad Roentgen, the
German physicist who discovered x-rays in 1895, first produced an image
of the bones in his wife’s hand. By 1900, every large hospital had an x-ray
machine. Nuclear magnetic resonance (NMR) technology was used to
determine chemical structures in the 1970s, and Magnetic Resonance
Imaging scanners were approved for human use in 1985. Chemical
contrasting agents and special film emulsions improve the diagnostic value
of x-rays, CT scans (three-dimensional x-ray imaging, computer
tomography), and MRI and ultra sound images.
The transilluminated
hand of Ms.Roentgen
Medical isotopes
Medical imaging has been much aided by the use of medical isotopes to
determine the function of internal organs, following the pioneering work
of Georg Hevesy, the Hungarian Nobel Laureate (1943). In 1935 Hevesy
determined the phosphor metabolism mechanism using radioactive
nuclides. Compounds are labeled with radioactive isotopes (such as
technetium-99m and thallium-201) or radio-opaques (such as barium and
iodine compounds). The radio-labeled compounds can then be tracked
through the body by gamma-detecting cameras to provide useful images
of the organs to which they are transported. The diagnostic applications
of medical isotopes include tumor detection, diagnosis of liver disease,
and the stress test for cardiac function.
Development of chemical assays
Today, we determine medical conditions by studying disease markers
or drugs residues that can be chemically detected in blood, urine,
feces, saliva, and perspiration. Laboratory testing, sophisticated
computer-assisted analytical instruments, and at-home testing all
measure fundamental chemical reactions. In the early 19th century,
diagnoses was based on observing clinical symptoms; if a patient
responded positively to a disease-specific treatment, then he or she
must have the disease. Diagnostic testing began in 1882 when Paul
Ehrlich observed that only the presence of typhoid bacillus (as
identified by a certain dye) could prove a diagnosis of typhoid fever.
Before, the diagnosis was based on the color of the patient’s skin.
Evolution of personal monitoring
Simplified at-home test kits facilitate the personal monitoring of human
health. For example, diabetic patients once had to visit a laboratory to
determine if sugar was present in their urine. In 1941, Miles Laboratories
introduced the first convenient sugar-in-urine assay for home use. Although
difficult to develop, dip-and-read urine tests were finally introduced in 1956.
In the 1960s, the first portable, battery-operated blood glucose meter was
introduced to work with chemical sticks to detect the glucose, considerably
improving the quality of life for diabetic patients. In the 1970s and 1980s,
home-use diagnostic kits for fecal occult blood, ovulation, pregnancy, and
strep were introduced.
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.6. Anti-infective Drugs
Salvarsan and Prontosil
Paul Ehrlich, the German bacteriologist, studied arsenic
compounds for their anti-bacterial properties and invented
Salvarsan in 1909 as a successful treatment for the fatal, sexually
transmitted disease, syphilis. This strategy was followed by other
researchers to find active compounds for combating infectious
diseases. The first sulfa drug, Prontosil, which was formerly used
as a textile dye, was discovered in 1932 as chemists searched for
an antibacterial drug that could cure the deadly streptococcal
infection, a common cause of chronic pneumonia. This discovery
was so important that the German biochemist Gerhard Domagk
received the 1939 Nobel Prize in medicine for his work in this
area. The active antibacterial agent of Prontosil was later
discovered to be sulphanilamide. Many other antibiotics were
then created from this agent, including Sulphapyridine in 1938.
The sulfa drugs were dramatically successful in reducing the
mortality rate of lobar pneumonia in the 1940s, and saved the
lives of millions. Their importance declined only with the advent of
the Penicillin era.
Alexander
Fleming
Penicillium notatum
Gerhard Domagk
Streptococcus
bacteria
Prontosil
Penicillin
In 1928, the Scottish bacteriologist, Alexander Fleming, discovered
a potent substance that could kill bacteria, which he isolated from a
naturally occurring mold (Penicillium notatum). Penicillin, a drug
based on this natural substance, was created during a massive
wartime project in 1943; it dramatically reduced infection and
amputation among injured soldiers in the American and British
armies throughout World War II. This natural Penicillin was so
expensive and rare that it had to be recycled from the urine of the
treated patients. Chemists attempted a new method of synthesis: to
artificially manufacture the natural substance on which the drug
was based. The chemical structure of penicillin was determined by
the British researcher, Dorothy Crowfoot Hodgkin in the 1940s,
enabling its synthesis. By 1957, several pharmaceutical companies
synthesized and commercially produced this drug. Their success
heralded the beginning of the modern era of antibiotic therapy.
Zidovudine (AZT)
Zidovudine (AZT) was approved in the United
States
for
the
treatment
of
Human
Immunodeficiency Virus (HIV) infection in 1987.
This drug was first synthesized in 1964, but proved
ineffective as a cancer chemotherapeutic. It was
abandoned until 1986, when its activity against
retroviruses was discovered by an American
research group. AZT and related nucleoside drugs
inhibit viral replication by targeting specific viral
enzymes. Because of the rapid development of
HIV’s drug resistance, first demonstrated with AZT,
mono-drug therapy can no longer be used to treat
HIV infection.
Zidovudine crystals
Zidovudine
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.7. Cardiovascular Management
Regulating heart beat
The ability of the local anesthetic Procaine to regulate the heart
beat (also called anti-arrhythmic activity) was discovered in the
1930s. This type of pharmaceutical treatment is complex and can
be quite difficult because the drugs that block arrhythmia can
also cause arrhythmia under certain conditions. Procaine was
the first of many drugs that were eventually approved for this
use. Procaine inhibits the cell membrane proteins known as
sodium channels. Procaine was followed by numerous drugs,
including beta-blockers and potassium or calcium channel
antagonists.
Treating heart failure
Digitalis glycosides, a group of compounds
that occur naturally in a number of plants,
have been used to treat heart failure for
centuries. After research identified how they
increase the force with which the heart
contracts, Digoxin was extracted from the
leaves of grecian foxglove (Digitalis lanata)
and approved in 1954 to treat atrial fibrillation
and congestive heart failure. It was eventually
discovered that anti-hypertensive drugs can
also be used to treat heart failure.
Busting blood clots
Heparin, a natural product isolated from animal livers, was first
used to precent thrombosis (blood clotting) during a blood
transfusion in 1935, and soon became the most commonly-used
anticoagulant (also called a blood thinner). It also prevents clot
formation during cardiac and arterial surgery. Wafarin (Coumadin)
an orally-active anticoagulant that prevents strokes and treats
heart attacks and thrombosis, was approved in 1955. During the
1970s, it was discovered that even once clots have formed, they
can be treated with thrombolytics. Utilizing enzyme activity to
dissolve blood clots led to Urokinase (1977), streptokinase (1978),
and the genetically engineered recombinant tissue plasminogen
activator, tPA (1987).
Arterioschlerosis
Controlling blood cholesterol levels
The buildup of cholesterol deposits inside arteries (arteriosclerosis) is a major
cause of coronary heart disease and strokes. Lovastatin (Mevacor) which
controls blood cholesterol levels (hypolipemic activity) by inhibiting a critical
enzyme from being converted into mevalonate, an early and rate-limiting step
in cholesterol biosynthesis, was approved in 1987. Subsequent and more
potent drugs, such as Simvastatin and Atorvastatin, have revolutionized the
treatment of high level of lipids in the blood (hyperlipidemia) by being highly
effective and well tolerated.
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.8. Cancer Chemotherapy
Evolution of cancer chemotherapy
The use of chemicals to treat cancer (cancer chemotherapy)
began in 1942 with the clinical use of nitrogen mustards by
Louis S. Goodman and Alfred Gilman. Drugs which block
folic acid (also called antimetabolites) were also developed.
Aminopterin (1947) was effective against leukemia, but its
adverse effects on white blood cells quickly led to its
replacement by methotrexate. In the 1950s, George
Hitchings and Charles Heidelberger developed the
antimetabolitic
mercaptopurine
for
leukemia
and
Fluorouracil for gastrointestinal and breast tumors.
Cytotoxic drugs
Cytotoxic drugs (or drugs which are poisonous to cells) were
isolated from plants and first introduced into cancer
chemotherapy in 1963. These anti-cancer drugs work on the
principle that rapidly proliferating cells, such as neoplastic (or
cancerous) ones, are more susceptible to damage by cytotoxic
drugs. Several variations include vinca alkaloids (vincristine and
vinblastine) isolated from periwinkle plants and podaphylotoxin
isolated from mayapple in 1970. Taxol was isolated from the
pacific yew in 1971 and developed to treat advanced breast
cancer and lung cancer in the early 1990s.
Tamoxifen
Tamoxifen, a synthetic molecule developed in 1971, was
introduced in 1977 to treat breast cancer by slowing the growth
of estrogen-dependent tumors. High estrogen levels promote
the cell proliferation in breast tissue, so this type of
chemotherapy blocks the natural hormones that can stimulate
growth of cancer cells. Megestrol is a synthetic derivative of
the naturally occurring steroid hormone, progesterone, which
functions in a similar manner and is used in the treatment of
recurrent breast tumours.
Mammographic
image of a breast
tumour
Personal
monitoring of
breasts promotes
early diagnosis
III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE
III.9. Novel Healthcare Materials
Artificial limbs and medical devices
Modern artificial limbs and organs, replacement joints,
contact lenses and hearing aids, and biomaterials which
are crafted from specialized plastics and other high-tech
materials have all been produced through chemistry. By
manipulating the structures of molecules and creating new
ones, chemists and engineers have developed new
medical materials that are strong, flexible, and durable. A
few such medical devices include the 1945 artificial
kidney, the 1950s prosthetic heart valves, and the 1982
surgical implantation of a permanent artificial heart. Plastic
contact lenses were introduced in 1956, and soft bifocal
contacts were refined in 1985.
Artificial
heart
valves
Artificial heart
Medical equipment
Chemistry is used to manufacture nearly all of
the plastic and vinyl medical devices used in
today’s hospitals and health care clinics. Today’s
medical equipment must be durable enough for
daily use while helping to create a clean, sterile,
and germ-free environment. Many routine
medical
processes
utilize
state-of-the-art
diagnostic equipment, stethoscopes, bandages
and other novel fabrics, syringes, surgical
instruments, blood bags, and plastic supplies that
are produced through chemistry. Even diapers
contain hygroscopic polymers that prevent
inflammation of the sensitive skin of babies.
Disinfectants and bleach
Chemistry makes it possible to sanitize your home, breakdown
mold and mildew, and remove stains. In the early 1900s, chemists
focused on controlling bacteria and cleaning clothes and home
surfaces effectively. In 1913, researchers developed a formula for
bleach that was affordable and easy to use. Today, bleach is a
household commodity and an effective disinfectant which
eliminates billions of germs and bacteria. Chlorine is also a
powerful weapon against diseases caused by viruses and bacteria
in homes, hospitals, and other buildings. Ignatius Semmelweis,
the Hungarian gynecologist, was the first to introduce hand
washing with chlorine water to his department in 1847.