toxicology case studies

Question 1

what % of global food crops are effected by mycotoxins

Answer 1

25%

Question 2

discuss the case study of the french company lactalis and its relevance

Answer 2

company who product babys formula (make cows milk more similar to human milk by adding nutrients)
two incidents of contamination with salmonella
relevance; 12 million boxes had to be recalled; massive economic importance

Question 3

which two species of fungus produce aflatoxins?
what do these species grow on?
under which conditions are aflatoxins produced>

Answer 3

aspergillus flavus and aspergillus parasiticus

animal feed

high humid environment. they are produced when the concentration of water in the air goes over a certain threshold

Question 4

discuss clinical symptoms of aflatoxiosis

Answer 4

GUT dsyfunction
vomiting
abdominal pain
reduce reproductivity
lung oedema and brain oedema leading to death/coma

Question 5

what are the main effects of aflatoxiosis

Answer 5

liver cancer and liver disease

Question 6

what is the toxic dose for aflatoxins in terms of primates

Answer 6

0.05mg/kg

Question 7

what is the FDA recommended threshold dose for aflatoxins

Answer 7

20 ppb total

0.5ppb for M1 in milk

Question 8

what are the four ways aflatoxins can be detected in food

Answer 8

solid phase extraction
thin layer chromatography
ELISA
mass spectrometry

Question 9

what are the ways aflatoxins can be detected in serum

Answer 9

immunoessays like ELISA

synchronous florescent spectroscopy

Question 10

how can detoxification of aflatoxins be done

Answer 10

ammoniation; the aflatoxins have their lactone ring broken and they are converted into different molecules which are less potent and toxic

Sodium bisulfate; treatment causes aflatoxin conversion into metabolites which are more water soluble and can easily be removed from biological material

chemisorbents; feed animal compounds HSCAS which bind tightly to aflatoxins and make them not bioavailable

Question 11

discuss two examples of contamination involving aflatoxins

Answer 11

1960’s england; 100,000 turkeys died because bird feed wasnt processed/stored under correct condtions

2013; contamination of animal feed in serbia meant cows with aflatoxiosis in germany etc; recall of milk and milk derived products

Question 12

why is the future concerning in terms of aflatoxins

Answer 12

more places will be of higher humidity due to global warming

Question 13

discuss ADME of aflatoxins

Answer 13

A;
ingestion of crops, milk etc
travel across placenta
inhalation of dust particles

D;
hepatic portal vein to liver (90% available)
also travels to kidneys and lungs

M;
cytochrome p450 in liver metabolises aflatoxins into less toxic derivitives like M1 but also sometimes into ROS like aflatoxin 8-9 epoxide which is unstable and binds to proteins causing toxicity and DNA casuing cancer if it effects the p53 suppressor gene

E:
bile pathway mainly
milk
urine

Question 14

discuess suspectable sub popualtions in terms of aflatoxins

Answer 14

sex
age
nutritional status
concurrent infections; those with viral hepatitus (HBV) always get cancer if exposed to aflatoxins

Question 15

how many people in developing countries are exposed to uncontrolled amounts of aflatoxins

Answer 15

4.5bn

Question 16

discuss the ADME of arsenic

Answer 16

A: arsenic is a naturally occuring compound due to both natural causes (volcanoes) and anthropogenic causes (smelting of metals, pesticides, antifungals). it is very water soluble so contaminates water but its also taken up by crops; rice crops in particular because they’re flooded with water

rice crops have 20 times the amount of aflatoxin of other cereal crops

those who eat rice, drink contmainated water or work in smelting operations become exposed via inhalation or ingestion

D:
the lungs are in close proximity to capillaries only 30% of the dose is absorped because mucus membranes work against the particles and some particles are too big to reach alveoli

90% of that which is ingested is absoped

most goes to lungs, some goes to skin, hair and nails

M:
it is methylated in the liver so it is more easily excreted

E: urine

Question 17

what are the biological effects of arsenic

Answer 17

neurotoxin
effects IQ development
effects immune development

Question 18

how can arsenic poisoning be detected

Answer 18

testing blood, urine and hair of a person

Question 19

name an area with soil geography and diets which leads to arsenic poisoning

Answer 19

bangladesh

Question 20

name a neonicitinoid

Answer 20

clothianidin

Question 21

what is the problem with neonicitinoids

Answer 21

they are neurotoxin to non target organisms like bees

Question 22

why do neonicitinoids persist in soil for a long time

Answer 22

it has a long half life

Question 23

discuss biological effects of neonicitinoids

Answer 23

effects colony success
effects memory ability
neurotoxic
impairs larval development

Question 24

state a fact about the extensive use of neonicitinoids

Answer 24

25% of global insecticide is neonicitinoids

Question 25

discuss a fact about the importance of pollinator insects

Answer 25

35% of global pollination relies of insects

£150 billion annually

Question 26

does do neonicitinoids end up in plants

Answer 26

the compound has low molecular weight and is highly soluble in water
once in the plant its transferred to pollen and nectar which bees feed on

Question 27

discuss problems sorrounding the research on neonicitinoids

Answer 27

extensive lab studies exist but not field studies
studies often involves overdosing
bees feed on many crops not just those with neonicitinoids; the concentration would be diluted
oilseed rape has been treated with neonicitinoids for a decade in UK. its requires insects for pollination and has remained a productive crop still