Kill or Cure - PowerPoint Presentation

Slide1

Kill or Cure

Medicine in the West:

the

r

ise

of

scienceSlide2

Aims

To introduce the idea and impact of laboratory medicine.

To see how the laboratory provided the context for the development of bacteriology.

To think about the role played by bacteriology in the shift from ‘dirt to germs’ in theories of disease causation.

To explore the history of genetics and its effects on modern medicine. Slide3

Part one

The rise of laboratory medicineSlide4

Introduction to laboratory medicine

From the latter half of the

18

th

C western

medicine witnessed fundamental changes. These were evident in medical theory:

the

ways in which the workings of the body in health and disease were understood.

The

spaces in which medical knowledge was developed and applied also underwent transformation. Laboratory medicine sought to explain the structure of the body at the cellular level and to describe its function as a complex series of dynamic processes.

The

laboratory usurped the hospital as the locus of research, and the laboratory scientist claimed a greater authority than the clinical practitioner. The diagnosis of particular infectious diseases now relied on tests on tissue samples performed at the lab bench, not simply on the subjective analysis of patterns of symptoms.

These changes that occurred were complex and interrelated. They proceeded at various rates in different parts of the western

world

.Slide5

Learning from the laboratory

The rising sciences of life:

Cell biology

and pathology (

 bacteriology and parasitology)

Physiological chemistry (

 experimental physiology)

P

harmacology

Techniques:MicroscopyHistologyVivisectionTools:MicroscopeSphygmographSpirometerThermometerScales, etc.

c. 1850s, esp. Germany

Nicholas Jewson, ‘The disappearance of the sick-man from medical cosmology, 1770-1870’,

Sociology

, (1976) 10; 225-44. Slide6

Part two

The ‘discovery’ of bacteriaSlide7

Bacteriology

Bacteriology is the study of bacteria.

Roy

Porter argues that the

development of bacteriology in the latter

part of the

19

th

C

brought one of medicine’s few true revolutions. The general thinking behind bacteriology (that diseases is due to tiny invasive beings) was not new (theories of contagion maintained that disease entities were passed from the infected party to

others). However it was only in the 19th C that the rise of patho-anatomy led to the belief that specific parasites and bacteria would be responsible for particular diseases. Slide8

Louis Pasteur 1822-1895, a

French chemist and biologist who proved the germ theory of disease and invented the process of

pasteurisation

.

Pasteur and Koch

Robert Koch 1843-1910, a

German physician and pioneering microbiologist. The founder of modern

bacteriology.

Slide9

A magic bullet is a perfect drug to cure a disease with no danger of side effects. The term magic bullet was first used in this sense by the German physician and scientist Paul Ehrlich who received the Nobel Prize in Physiology or Medicine in 1908.

Initially, Ehrlich invoked the notion of a magic bullet in characterizing antibodies. He then reused the concept of a magic bullet to apply to a chemical that binds to and specifically kills microbes or tumor cells.

Ehrlich's best known magic bullet was

arsphenamine

(

Salvarsan

, or compound 606), the first effective treatment for syphilis. At a meeting in 1910, Ehrlich and his colleagues announced the remarkable effects of their treatment of syphilis with this magic bullet.

‘Magic bullets’Slide10

The organism suspected of causing a particular disease could be discovered in every instance of the disease.

When extracted from the body, the germ could be grown in the laboratory and maintained for several generations.

When this culture was injected into animals, it should induce the same disease observed in the original source.

The organism could then be retrieved from the experimental animal and cultured again.

Koch’s postulates Slide11

Part three

From ‘dirt’ to ‘germs’Slide12

Malaria, a disease transmitted by mosquitoes and still widespread in many tropical areas of the world, was once endemic in temperate latitudes.

La

Mal’aria

, by A. Hebert, which hangs in the

Mus

é

e d’Orsay, Paris, shows a group of people in the Pontine marshes as a result of malaria. Prior to the late

19

th

C it

was assumed that the disease emanated directly from evil-smelling marshes – hence the name ‘

mal’aria

’, literally meaning ‘bad air’.

MiasmaSlide13

Cholera

John Snow (1813-1858) observed a correlation between the disease and where it spread, and with the source of public water.

In

1855, he published

On the Mode of Communication of Cholera

. This treatise was a milestone in public health as it correctly identified the fecal-oral route of human infection and offered powerful arguments for the germ theory.

John Snow, Broad Street Pump, 1855Slide14

The Pasteur Institute, Paris, 1888. The institute was built in Paris in 1888 both to honour the work of Louis Pasteur and to provide a base for his further research.

Bacteriology and the ‘grand research institutes’Slide15

Bacteriology and disease control

Firstly the

discovery of the identity of disease-causing pathogens gave rise to hopes that particular complaints could be prevented and treated by new vaccine

therapies.

Secondly bacteriology enabled disease

control

through the

isolation of infected

persons. While isolation was not new, bacteriological

tests

gave authorities

accurate knowledge of the identity and presence of

disease.

London Open Air Sanatorium

for Tuberculosis, c.1907

Louis Pasteur and the rabies cure, 1885Slide16

Max von

Pettenkofer

(1818-1901).

Pettenkofer’s

name is most familiar in connection with his work in practical hygiene, as an apostle of good water, fresh air and proper sewage disposal. His attention was drawn to this subject by the unhealthy condition in Munich in the 19th century.

Sanitary reform and public healthSlide17

Part four

From ‘germs’ to ‘genes’Slide18

Founding fathers

Gregor Johann Mendel

(1822-1884). A scientist

and Augustinian

friar. Published ‘Experiments

in Plant

Hybridization’ in1865.

The

‘founder’

of the modern science of

genetics. He discovered the basic principles of heredity through experiments breeding plants. He showed that some traits such as height or flower color do not appear blended in their offspring. His work also demonstrated that variations in traits were caused by variations in inheritable factors.Charles Robert Darwin (1809-1882). An

English naturalist and geologist, best known for his contributions to evolutionary theory. Published the Origin of Species in 1859. The rise of Darwinism also led to the advancement of eugenics.

Darwin had concluded his explanations of evolution by arguing that the greatest step humans could make in their own history would occur when they realized that they were not completely guided by instinct. Rather, humans, through selective reproduction, had the ability to control their own future evolution. Slide19

Mendel’s heirs

The word

gene

was first used in 1909 by the Danish botanist Wilhelm

Johannsen

to describe the Mendelian units of heredity.

The

American geneticist Thomas Hunt Morgan

studied

the segregation of mutations in the fruit fly. Morgan used mutations to move beyond the laws that managed heredity to examine the specific mechanisms—the genes themselves—that carry out the process. By finding and breeding hundreds of visible mutants, including those with variations in body color and wing shape, he

created chromosome maps that showed where on each of the fruit fly’s 4 chromosomes certain genes lay. The fact that genetic linkage corresponded to physical locations on chromosomes was shown later, in 1929, by Barbara McClintock, in her cytogenetic studies on maize.

Illustration from Morgan’s,

A Critique of the Theory of Evolution (1916)Slide20

DNA

One of Watson and Crick’s original models for the structure of DNA.

James Watson and Francis Crick, 1959

In the 1950s, at the Cavendish Laboratories in Cambridge, England, scientists developed X-ray crystallography, a technology that made it possible to interpret the three-dimensional structure of a crystallized molecule.

It

allowed Maurice Wilkins and Rosalind Franklin to take "snapshots" of DNA that were used in 1953 by James Watson and Francis Crick to build their now-famous model:

DNA

was shaped like a spiral staircase, or double helix.

Their

discovery of the actual physical structure of DNA finally created a consensus among geneticists that genes were real. Slide21

The age of molecular genetics

1970

- Arber and Smith - First restriction enzyme, Hind II, is isolated

1970 - Baltimore and Temin - Discovery of reverse transcriptase

1972 - Berg - First recombinant DNA molecule is constructed

1973 - Boyer and Cohen - First functional recombinant E. coli cell produced

1977 - Sanger and Gilbert - DNA sequencing techniques are described

1977 - Sharp and Roberts - Introns discovered

1978 - Botstein - RFLPs launch the era of molecular mapping of linkage groups

1980 - Sanger Group - First genome is sequenced, the bacteriophage ΦX174 of E. coli1983 - Mullis - PCR technique is discovered1986 - Hood, Smith, Hunkapiller

and Hunkapiller - First automated DNA sequencer1990 - US Government - Human Genome Project launched1995 - Celera - First bacterial genome (H. influenza) is sequenced1996 - Yeast Genome Consortium/ First eukaryotic genome (yeast) sequenced 2000 - Arabidopsis Genome Initiative - First flowering plant genome (Arabidopsis thaliana) is  sequenced2001 - The human genome sequence is publishedSlide22

The new eugenics?

Medical

genetics

encompasses a wide range of health concerns, from genetic screening and

counseling

to

fetal

gene manipulation and the treatment of adults suffering from hereditary disorders.

Applications of the Human Genome Project are often referred to as “Brave New World” genetics or the “new eugenics”.Slide23

Conclusions

The advent of bacteriology was transformative

in

understanding

of

diseases.

However

the

extent to which bacteriological science led to the decline in epidemic disease is harder to

assess.New germ practices were used alongside old sanitary reforms.The

transformation of genetic medicine from a marginal field in the 1950’s to a core activity of biomedicine was a major development in modern science. The past two decades we have witnessed an increase and more intense focus on the genetic and biological basis for disease. However at least the 18th C scientists, doctors and patients had tried to establish links between heredity and disease.