Download Math 210G Mathematics Appreciation Dr. Robert Smits

Math 210G
Mathematics Appreciation
Dr. Joe Lakey
website:
http://www.math.nmsu.edu/~jlakey/home.html
phone: 505-646-2417
office: Science Hall 230
Theories of disease
• Ancient historical view: spontaneous generation
• Atharvaveda: ancient Hindu text deals with
medicine. Identifies causes of disease as living
causative agents
• Earliest western references: “On Agriculture” by
Marcus Terentius Varro (c. 36 BC): “...and
because there are bred certain minute
creatures which cannot be seen by the eyes,
which float in the air and enter the body through
the mouth and nose and there cause serious
• Avicenna (1020 AD) :
bodily secretion
contaminated by foul
foreign earthly bodies
before being infected;
contagious nature of
tuberculosis/infectious
diseases; introduced
quarantine
• Black Death bubonic plague 14th century
• Ibn Khatima: hypothesized infectious
diseases caused by "minute bodies”
• Ibn al-Khatib: “On the Plague”:
•
”…notices how he who establishes
contact with the afflicted gets the disease,
whereas he who is not in contact remains
safe, and how transmission is affected
through garments, vessels and earrings."
• The History of the Black Death.avi
Fracastoro (1478-1553)
Redi(1626-1697)
Girolamo Fracastoro (1546): epidemics caused by
“transferable seedlike entities” direct or indirect
contact OR long distances.
Francesco Redi (1668): proof against spontaneous
generation. 3 jars. meat loaf. (1) open, (2) covered
with gauze (3) sealed. After a few days…
(1) covered by maggots, (2) maggots on surface of
the gauze (3) none.
maggots only on surfaces accessible by flies.
No spontaneous generation
Agostino Bassi (1773-1856)
• Credited with “germ theory”
of disease
• observations on
muscardine disease of
silkworms. 1835: blamed
deaths of insects on a
contagious, living agent,
visible to the naked eye
powdery spores
• Ignaz Semmelweis (1818-1865)
Hungarian obstetrician Vienna's
Allgemeines Krankenhaus in 1847,
• high incidence of death from puerperal
fever amongst women who delivered
at the hospital (30%.)
• physicians had usually come directly
from autopsies.
• made doctors wash their hands with
water and lime … reducing mortality
from childbrith < 2%
• theories were viciously attacked by
most of the Viennese medical
establishment.
John Snow
•
•
•
•
1854 Broad Street cholera outbreak
miasma (Greek: "pollution") "bad air"
germ theory: microorganisms
Snow: “statistical” analysis
• RSC honours Dr John Snow.avi
Snow and Cholera (1813-1858)
1854 Broad Street cholera
outbreak
—John Snow, letter to the editor of the Medical
Times and Gazette
• “… nearly all the deaths had taken place within a short distance of
the [Broad Street] pump… only ten deaths in houses situated
decidedly nearer to another street-pump. In five of these … they
always sent to the pump in Broad Street…. In three other cases, the
deceased were children who went to school near the pump in Broad
Street... With regard to the deaths occurring in the locality belonging
to the pump, there were 61 instances in which I was informed that
the deceased persons used to drink the pump water from Broad
Street, either constantly or occasionally...
• The result of the inquiry, then, is, that there has been no particular
outbreak or prevalence of cholera in this part of London except
among the persons who were in the habit of drinking the water of the
above-mentioned pump well.
•
I had an interview with the Board of Guardians of St James's
parish, on the evening of the 7th inst [Sept 7], and represented the
above circumstances to them. In consequence of what I said, the
handle of the pump was removed on the following day.
Light microscope
• ~1590, two Dutch spectacle makers, Zaccharias Janssen and his
son Hans, while experimenting with several lenses in a tube,
discovered that nearby objects appeared greatly enlarged.
• 1609, Galileo, … heard of these early experiments, worked out the
principles of lenses, and made a much better instrument with a
focusing device.
• Anton van Leeuwenhoek (1632-1723) …taught himself new
methods for grinding and polishing tiny lenses of great curvature …
magnifications up to 270 diameters, … He was the first to see and
describe bacteria, yeast plants, the teeming life in a drop of water,
and the circulation of blood corpuscles in capillaries.
• Robert Hooke, the English father of microscopy, re-confirmed
Anton van Leeuwenhoek's discoveries of the existence of tiny living
organisms in a drop of water. Hooke made a copy of
Leeuwenhoek's light microscope and then improved upon his
design.
The microscope
• first microscope was
made around 1595 in
Middleburg, Holland
• Galileo Galilei's
compound
microscope in 1625
• Hooke’s (pictured)
Antonie van Leeuwenhoek (1632-1723)
… discovered bacteria observing plaque between his own teeth
…under a microscope
On September 17, 1683, Leeuwenhoek wrote to Royal Society,
"a little white matter, which is as thick as if 'twere batter."
Repeated observations on … presumably wife and daughter…,
and on two old men who had never cleaned their teeth
… "I then most always saw, with great wonder, that in the said
matter there were many very little living animalcules, very prettily
a-moving. … The biggest sort. . . had a very strong and swift
motion, and shot through the water (or spittle) like a pike does
through the water. The second sort. . . oft-times spun round like a
top. . . and these were far more in number."
Van Leeuwenhoek’s discovery of bacteria was not
immediately accepted by scientists. …
… the Society appointed two scientists - Nehemiah Grew,
the plant anatomist and Robert Hooke, the microscopist.
First time they failed, casting doubts on his report.
However, Hooke again tried using a microscope with 330
X (power of magnification) and confirmed
Leeuwenhoek’s success. Both scientists confirmed that
their observations were similar to those described in the
letters by Leeuwenhoek.
Now, the Royal Society accepted Leeuwenhoek as
scientist and declared him as the discoverer of bacteria.
Louis Pasteur (1822-1895)
• (1860-1864)
fermentation and
growth of
microorganisms in
nutrient broths.
• Filters stop particles
passing through to the
growth medium: no
growth implies no
spontaneous
generation
Robert Koch (1843-1910)
• First to devise proofs to
verify germ theory.
• Koch's Postulates (1875)
demonstrated anthrax
caused Bacillus anthracis.
• Postulates still used today
to help determine if newly
discovered disease caused
by a microorganism.
• Casimir Davaine (1850s)
bacterium= "rod"or "staff".
• 3 types:
• bacillus; rectangular with
sharply rounded ends,
which varies in diameter
between 20 µm and 0.5
µm.
• coccus; which resembles
two tiny beans lying face
to face. This type of
bacteria is about 0.5 µm
in diameter.
• spiral, which is about 15
µm in length.
Viruses
Viruses are small
Pasteur: could not find “the germ” some diseases,
such as rabies (and common cold, mumps,
measles and polio)
• Rabies :almost always fatal. Noted weakened
extract of tissue infected with rabies might be
protective against the disease, even after a
person had been bitten.
• Pasteur 1885 applied
extract 9-year-old
Joseph Meister who
had been bitten by a
rabid dog. Vaccine
worked. Joseph
Meister lived another
55 years.
• Pasteur hypothesized
rabies due to small
bacteria.
Jenner (1749-1823) : smallpox
• 18th-c. Europe ~ 95 % pop.
contracted smallpox at some point in
their lives
• as many as one in 10 died of it.
• New World: wiped out millions of
Native Americans.
• Edward Jenner (1796): milkmaids
got cowpox (milder) but rarely
smallpox.
• Could exposure to cowpox protect
against smallpox as well?
• Smallpox: survivors thereafter immune.
• Jenner: cowpox imply smallpox immunity?
• Tested on a healthy 8-year-old James
Phipps: pus from milkmaid's cowpox sore,
scratched into the boy's arm. Small infected
spot soon subsided.
• 6 weeks later: inoculated Phipps with
smallpox. Phips never contracted smallpox.
• Academy of Achievement's Exclusive
Interview Jonas Salk.avi
Martinus Beijerinck (1851-1931)
and Dmitri Ivanovsky (18641920)
• Germ theory accepted by late 19th century
• Dmitri Ivanovsky (1892) tobacco mosaic disease, … was clearly
infectious; …Hoping to find bacteria Ivanovsky ran extract of diseased
leaves through filter, … pores small enough to trap any known
bacteria…caused ….went right through …liquid retained the power to
infect other plants.
• Ivanovsky published findings… little attention was paid …
• Martinus Beijerinck (1898) … same experiments … same results
• infectious agent destroyed when the liquid was heated.
• Beijerinck concluded agent was a "contagious living fluid."
• Beijerinck (as Jenner) used the term "virus" (Latin for poison or
pestilence.
• hoof-and-mouth disease, yellow fever, … were also caused by these
"filterable viruses."
• .
• 1930s filters with pores tiny enough to prove that viruses are
particulate after all, rather than being fluid in nature.
• The earliest electron microscopes also appeared in the 1930s, and
viruses could at last be seen.
• Today we know that viruses are not living cells like bacteria, but rather
tiny packets of genetic material that must infect the cells of their
unwilling host in order to reproduce.
Viruses are small
Largest viruses ~
1/10 typical
bacteria ~ 0.2–2.0
µm
• NOT simply
miniature bacteria
• Ångström (1868) :
wavelength of
electromagnetic radiation
in multiples of one tenmillionth of a millimetre,
• (Ångström unit)
• Humans: 4,000 å (violet)
to 7,000 å (dark red) so
the use of the ångström
as a unit provided
Electron microscope
• uses electrons to illuminate specimen
and create image.
• can magnify specimens up to 2
million times,
• best light microscopes : 2000 times.
Both electron and light microscopes
have resolution limitations, imposed
by their wavelength.
• wavelength of an electron much
smaller than that of a light photon
• electrostatic and electromagnetic
lenses … by controlling electron
beam ..in a manner similar to lenses
in light microscope
Other deadly diseases
Smallpox
• Smallpox (430 BC? - 1979):
• 30 to 35 % mortality rate
• Smallpox killed an estimated 60 million
Europeans, including five reigning European
monarchs, in the 18th century alone.
• and most of the native inhabitants of the
Americas 90 to 95 %
• Killed more than 300 million people worldwide
in the 20th century alone,
Spanish flu
• Spanish Flu (1918 - 1919): (2.4 % to 5% of world
population at the time);
• Killed 50 to 100 million people worldwide in less than 2
years
•
WWI blamed as factor in its spread
• …more people than Hitler, nuclear weapons and all the
terrorists of history combined.
• The pandemic came and went like a flash…in the United
States a quarter of the nation's population -- and a billion
people worldwide -- had been infected
• Obama on the spanish flu.avi
Cholera
• Cholera (1817 - today): (bacterium Vibrio cholerae.)
• 8 pandemics; hundreds of thousands killed worldwide
• Transmission to humans occurs through ingesting
contaminated water or food
• The major cholera pandemics are generally listed as:
First: 1817-1823, Second: 1829-1851, Third: 1852-1859,
Fourth: 1863-1879, Fifth: 1881-1896, Sixth: 1899-1923:
Seventh: 1961- 1970, and some would argue that we are
in the Eighth: 1991 to the present. Each pandemic, save
the last, was accompanied by many thousands of
deaths. As recently as 1947, 20,500 of 30,000 people
infected in Egypt died. Despite modern medicine,
cholera remains an efficient killer.
Typhus
• Typhus (430 BC? - today) (bacterial)
• Charles Nicolle 1909 : lice were the vectors for
epidemic typhus.
• Killed 3 million people between 1918 and 1922
alone
• Common major outbreaks during wars
• .Following the development of a vaccine during
World War II epidemics occur only in Eastern
Europe, the Middle East and parts of Africa.
Malaria
• Malaria (1600 - today):
• Malaria is a vector-borne infectious disease caused by
protozoan parasites transmitted by female Anopheles
mosquitoes (plasmodium)
• widespread in tropical and subtropical regions
• about 400–900 million cases of fever and approximately
one to three million deaths annually —
• little change in which areas are at risk of this disease
since 1992.
• death rate could double in the next twenty years.
• the majority of cases are undocumented.
AIDS
• AIDS (1981 - today): (retrovirus)
• Killed 25 million people worldwide: one of the most
destructive epidemics in recorded history
• first recognized in 1981,
• claimed approximately 3.1 million in 2005, including
570,000 were children.
• There are an estimated 40.3 million (estimated range
between 36.7 and 45.3 million) people now living with
HIV.
• The key facts surrounding this origin of AIDS are
currently unknown, particularly where and when the
pandemic began, though it is said that it originated from
the apes in Africa.