Arsenic: The Dark and the Light - PowerPoint PPT Presentation

1 / 15
About This Presentation
Title:

Arsenic: The Dark and the Light

Description:

In the C19 arsenic was used extensively. Examples: wallpapers, textiles contained arsenic. ... 30 million rolls of wallpaper made per annum in Britain by the ... – PowerPoint PPT presentation

Number of Views:77
Avg rating:3.0/5.0
Slides: 16
Provided by: shahnam1
Category:

less

Transcript and Presenter's Notes

Title: Arsenic: The Dark and the Light


1
  • Arsenic The Dark and the Light
  • John Emsley, The Elements of Murder, Oxford
    Oxford UP, 2005  

2
Arsenic
  • In the C19 arsenic was used extensively.
  • Examples wallpapers, textiles contained arsenic.
  • Scheeles green (copper arsenite), or CCA, was
    used as a wood preservative in treated pine until
    relatively recently.
  • Essential element? Ca 0.1 ppm in humans

3
Insidious Arsenic
  • 30 million rolls of wallpaper made per annum in
    Britain by the 1870s.
  • 4/5 contained arsenic.
  • Thought dangerous from 1815.
  • Initially dust was suspected.
  • Microbes shown to be involved.
  • Eventually confirmed in 1932 that trimethylarsine
    was the culprit.

4
One for the X-Files
  • The US Ambassador to Italy suffered arsenic
    poisoning in the 1950s.
  • The Ambassador, Clare Boothe Luce, had chosen to
    sleep in a room not previously used as a bedroom.
  • The ceiling was highly decorated and arsenic
    pigments had been used.
  • Vibrations caused by a washing machine on the
    floor above caused the formation of arsenic-rich
    dust.

5
Arsenic Eaters
  • Peasants in the Styrian Alps, between Hungary and
    Austria, regularly consumed large doses of
    arsenic trioxide.
  • Started with 30 mg twice a week, then increased
    the dose to around 100 mg per day.
  • The Styrian Defence.
  • Interferes with iodine metabolism leading to
    thyroid problems.

6
Lewisite
  • Lewisite is a compound containing arsenic that
    was developed during WW I as a chemical weapon.
  • BAL (British AntiLewisite) was developed prior
    to WW II as an antidote.
  • BAL has been used in cases of heavy metal
    poisoning.

7
Arsenic in Beer
  • A case of mass arsenic poisoning occurred in
    Birmingham in 1900.
  • About 6000 people poisoned.
  • 70 died.
  • Glucose that was used in beer-making was
    contaminated.
  • The sulfuric acid used in preparing the glucose
    was made from iron pyrites with significant As
    present.
  • Beer had ca 15ppm As (6pts 45mg)

8
Arsenic in Groundwater
  • Much of Bangladesh is low-lying with a chronic
    problem being the supply of clean water for
    villages.
  • A WHO sponsored project sank many tube wells in
    Bangladesh.
  • Water and oxygen has caused the oxidation of
    arsenic-containing minerals mobilising the As
    into groundwater.
  • About 90 of Bangladeshis drink well water.

9
Fowlers solution
  • Described in 1786 by Thomas Fowler, a medical
    practitioner in Stafford.
  • Followed use of arsenic by Paracelsus and van
    Helmont.
  • Used in C19 as a treatment for malaria.
  • Found to have significant effect on a leukaemia
    patient in 1865.
  • This use persisted until the 1940s.

10
Sleeping sickness
  • Livingstone recommended Fowlers solution for the
    treatment of sleeping sickness.
  • Sleeping sickness was found to be due to
    trypanosomes (T brucei).
  • The trypanosomes could be temporarily eliminated
    by the administration of Fowlers solution.
  • Mortality could be as high as 75.

11
Atoxyl
  • The compound known as Atoxyl was synthesised in
    1863.
  • Found to be inactive against trypanosomes in
    culture.
  • Tests in 1905 in Liverpool indicated that Atoxyl
    was effective in treated infected animals.
  • Used therapeutically would require constant
    medication for 6 mo., leading to blindness.

12
Arsphenamine
  • Analogues of Atoxyl were tried against
    trypanosomes with some success.
  • The compounds that Ehrlich and colleagues had
    developed were tested on Treponema palladium, the
    causative agent of syphilis (isolated 1905).
  • Once efficacy had been proved 65000 samples sent
    to physicians for trial.
  • Marketed as Salvarsan.

13
Arsenic and cancer
  • In the late C19 it was discovered that users of
    Fowlers solution developed skin cancers.
  • Inorganic arsenic is the problem.
  • Implicated in bladder, lung and liver cancer.
  • Trisenox is used in the treatment of acute
    promyelocytic leukaemia (APL).
  • Trisenox is a modern version of Fowlers
    solution.

14
Trisenox
  • Chinese physicians in Harbin reintroduced
    arsenicals as anti-cancer agents from the 1970s.
  • Particularly successful in the treatment of APL.
  • Low plasma concentrations (1-2mM) are effective
    mild side effects.
  • Remission rates between 85 93.
  • Therapy being trialled for other leukaemias.

15
Other references
  • Walter Sneader, Drug Discovery A History, New
    York Wiley, 2005.
  • John Timbrell, The Poison Paradox, Oxford Oxford
    UP, 2005.
  • Gielen and Tiekink, (eds.), Metallotherapeutic
    Drugs and Metal-based Diagnostic Agents, New
    York Wiley, 2005.
Write a Comment
User Comments (0)
About PowerShow.com