Concept and Principles of Toxicology (1)

8/9/2019 Concept and Principles of Toxicology (1)

1/73

Principles ofPrinciples of

Toxicology :Toxicology :

The Study of PoisonsThe Study of PoisonsPM Dr Mohd Khan Ayob

PPSKTM, FST

Universiti Kebangsaan Malaysia

125/05/2010 MohdKhan(c)2011


2/73

To know scope and denitionof toxicology,

Describe how toxicologist

work and manage toxicants,

To know basic principles oftoxicology.

225/05/2010 MohdKhan(c)2011


3/73

IntroductionIntroduction

Are all substances toxic?

YS! "oo# at these$

% Sugar has an "D&' o( )',''' *g+#g

% thanol has an "D&' o( ),-'' *g+#g

% Table salt has an "D&' o( ),-&' *g+#g

% .ater has an "D&' o( slightly greater than

/',''' *g+#g

0Synthetic1 does not *ean toxic or 2oisonous

03atural1 does not *ean sa(e or even lo4 ris#

D!":The amount (dose) of achemical whichproduces death in 50%

of a population of testanimals to which it isadministered by any ofa variety of methods.Normally expressed asmilligrams ofsubstance per ilogram

ofanimal body weight(mg!g)

325/05/2010 MohdKhan(c)2011


4/73

4

567 o( all 2oisonings ha22en at ho*e8

The household 2roducts i*2licated in *ost

2oisonings are$ cleaning solutions, (uels,*edicines, and other *aterials such asglue and cos*etics8

9ertain ani*als secrete a xenobiotic 2oisoncalled veno*, usually in:ected 4ith a bite

or a sting, and others ani*als harborin(ectious bacteria8

So*e household 2lants are 2oisonous tohu*ans and ani*als8

Do You Know?Do You Know?

25/05/2010 MohdKhan(c)2011


5/73

Did you know that....(in the USA)Did you know that....(in the USA)

About ; *illion toxic ex2osures

annually

% Fe4er than 7 o( overdose 2atientsthat reach the hos2ital result in (atality

< =ut )>)&7 *ortality i( arrive in dee2

co*a

ne (ourth o( suicide atte*2ts are

via drugs

525/05/2010 MohdKhan(c)2011


6/73

Leading causes of pharmaceuticalLeading causes of pharmaceutical

death death

Analgesics Tricyclic antide2ressants

Sedative+hy2notics

Sti*ulants and street

drugs

9ardiovascular drugs Alcohols

625/05/2010 MohdKhan(c)2011


7/73

o!icology" an old fieldo!icology" an old field

Toxicology is arguably the oldest scienti(ic disci2line,

as the earliest hu*ans had to recogni@e 4hich 2lants

4ere sa(e to eat8

Yes!3o!

725/05/2010 MohdKhan(c)2011


8/73

u*ans are ex2osed to che*icals both

deliberately and inadvertently8

% Most exposure of humans to chemicals is via naturally

occurring compounds consumed in the diet from foodplants.

9he*icals are natural, biological, or synthetic in

origin% 3atural B(ood, *etals, *ineralsC% =iological Btoxins (ro* bacteriaC

% Synthetic*anu(actured through che*ical 2rocesses

A22roxi*ately '',''' che*icals are currently

in use 4orld4ide8 &'' ne4 (or*ulations enter

the *ar#et2lace annually8

825/05/2010 MohdKhan(c)2011


9/73

#hat is o!icology$#hat is o!icology$

ld de(inition$ the basic science o( 2oisons

3e4 De(inition$ the study o( the adversee((ects o( che*ical agents on biological

syste*s

The ulti*ate goal is to increase ourunderstanding o( ho4 che*icals a((ect

hu*an health8

925/05/2010 MohdKhan(c)2011


10/73

Toxicoo!" # T$%&inoo!i$'Toxicoo!" # T$%&inoo!i$'

.hat is toxicology? The study of the effects ofpoisons.

Poison = Toxicant , Toxin and/or Xenobiotic

Poisonous substances (Toxins) are produced byplants, animals, or bacteria.

Phytotoxins

Zootoxins

Bacteriotoxins

1025/05/2010 MohdKhan(c)2011


11/73

What is a Toxicant?What is a Toxicant?

The ter* toxicant re(ers to toxic substances >

2roduced by or are by>2roducts o( hu*an>*ade

activities8

% eavy Metals

% Solvents and Ea2ours

% adiation and adioactive Materials

% Dioxin+Furans

% Pesticides

1125/05/2010 MohdKhan(c)2011


12/73

Gecall$ Foreign che*icals aresynthesi@ed 4ithin the body areter*ed xenobiotics BHr8Xenos*eaning 0strange1CG

Ienobiotics *ay be naturallyoccurring che*icals 2roduced by2lants, *icroorganis*s, or ani*alsBincluding hu*ansC8

Ienobiotics *ay also be synthetic che*icals 2roduced byhu*ans8

What is a XenobioticWhat is a Xenobiotic

Poisons are xenobiotics, but not all xenobiotics are poisonous8

1225/05/2010 MohdKhan(c)2011


13/73

% #hat is% #hat is o!ico!ic$$

This ter* relates to 2oisonous or

deadly e((ects on the body by

% inhalation BbreathingC,

% ingestion BeatingC, or

% absor2tion, or by

% direct contact 4ith a che*ical8

25/05/2010 MohdKhan(c)2011 13


14/73

% #hat is a% #hat is a o!ic Symptomo!ic Symptom$$

Any (eeling or sign indicating the

2resence o( a 2oison in the syste*8

25/05/2010 MohdKhan(c)2011 14


15/73

% #hat are% #hat are o!ic &ffectso!ic &ffects$$

The health e((ects that occur due to

ex2osure to a toxic substanceJ also

#no4n as a 2oisonous e((ect on thebody8

25/05/2010 MohdKhan(c)2011 15


16/73

#hat is#hat is o!icityo!icity$$

the degree to 4hich a substance is

2oisonous or can cause in:ury8

% The toxicity de2ends on a variety o((actors$

< dose, duration and route o( ex2osure, sha2e

and structure o( the che*ical itsel(, and

< individual hu*an (actors8

25/05/2010 MohdKhan(c)2011 16


17/73

% #hat is% #hat is Selecti'e o!icitySelecti'e o!icity$$

A toxic che*ical that 2roduces in:ury to

one #ind o( living *atter 4ithouthar*ing another (or* o( li(e, even

though the t4o *ay co>exist8

25/05/2010 MohdKhan(c)2011 17


18/73

ToxicologyToxicology

The science that deals 4ith har*(ul or

adverse e((ects o( toxcicants Bche*icalsC on

living organis*s and assesses the2robability Bris#C o( their occurrence8

The inter(ace o( che*istry and biology8

% Toxicology$ toxicosis or disease e((ectES

% Phar*acology$ thera2eutic e((ect

1825/05/2010 MohdKhan(c)2011


19/73

#. Toxicant$ Toxin$ Poison$ %a&ard any agent capable of producing a

deleterious response in a biological system

'. (d)erse$Toxic e*ects any unwanted change (damage) from an

organism"s normal state dependent upon the concentration of active

compound at the target site (receptor)for asu#cient time.

+. i)ing organism cellular target sites! storage depots and

en$ymes1925/05/2010 MohdKhan(c)2011


20/73

OMMON TOXI OLOGY

OMMON TOXI OLOGY

QUESTIONS

UESTIONS

#. hatis a poison-

'. heredose it come from- exposure /0

+. %owdoes it get into li)ing organism-exposure /0

1. hatdoes it do to li)ing organism-

mechanism /0!. %owcan we treat$pre)ent this toxicity-

clinical /0

2025/05/2010 MohdKhan(c)2011


21/73

lassification of o!ic Agentslassification of o!ic Agents

eavy Metals

Solvents and Ea2ours

adiation and adioactive Materials

Dioxin+Furans

PesticidesPlant Toxins

Ani*al Toxins

25/05/2010 MohdKhan(c)2011 21


22/73

Sucategories of o!ic SustanceSucategories of o!ic Sustance

lassificationslassifications ((ect on target organs Bliver, #idney, he*ato2oietic

syste*C,

Use B2esticide, solvent, (ood additiveC,

Source o( the agent Bani*al and 2lant toxinsC,

((ects Bcancer *utation, liver in:uryC,

Physical state Bgas, dust, liuidC,

"abeling reuire*ents Bex2losive, (la**able, oxidi@erC,

9he*istry Baro*atic a*ine, halogenated hydrocarbonC, or

Poisoning 2otential Bextre*ely toxic, very toxic, slightly

toxicC

25/05/2010 MohdKhan(c)2011 22


23/73

*eneral lassifications of Interest*eneral lassifications of Interest

to ommunitiesto ommunities

Air 2ollutants

ccu2ation>related

Acute and chronic 2oisons

25/05/2010 MohdKhan(c)2011 23


24/73

25/05/2010 24

The science of Toxicology helps peopleThe science of Toxicology helps people

maemae

informed decisions and balanceinformed decisions and balance&'' vs. *N*+&T'&'' vs. *N*+&T'

The study foundThe study found

the highest le)elsthe highest le)els

of pesticideof pesticide

residues inresidues inpeaches, apples,peaches, apples,

pears22.pears22.

(3D Spinach.(3D Spinach.

MohdKhan(c)2011


25/73

he Scope of o!icologyhe Scope of o!icology

< Toxicoloy related closely to< Pharmacology,< Biochemistry,

< Molecular biology,< Chemistry,< Epidemiology,< Pathology,< Genetics,< Public Health,< Medicine,< etc.

2525/05/2010 MohdKhan(c)2011


26/73

27

Su+disciplines of o!icologySu+disciplines of o!icology

nviron*ental Toxicologyccu2ational BLndustrialC ToxicologyFood 3utritional Toxicology9linical ToxicologyForensic ToxicologyDescri2tive Toxicology

Mechanistic Toxicologyegulatory ToxicologyAnalytical Toxicology

25/05/2010 MohdKhan(c)2011


27/73

28

Environmental ToxicologyEnvironmental Toxicology

Studies che*icals that are conta*inantso( (ood, 4ater, soil, or the air8

Deals 4ith toxic substances that enter

the 4ater4ays, such as la#es, strea*s,rivers and oceans8

Fact$ Most co**on 2roble*s include4ater>borne bacteria and viruses,

4aste heat (ro* electrical 2lants,radioactive 4astes, se4age, andindustrial 2ollution8

25/05/2010 MohdKhan(c)2011


28/73

29

ccupational !"ndustrial#ccupational !"ndustrial#

ToxicologyToxicology Protects !or"ers from toxic substances and

ma"es their !or" en#ironment safe.

$act%&ccupational diseases caused by industrial chemicals

account for an estimated ', to , deaths and

*', ne! cases of illness each year in the +nited tates.

25/05/2010 MohdKhan(c)2011


29/73

30

Food ToxicologyFood Toxicology

$ood toxicoloy is the study of the nature, properties,

effects, and detection of toxic substances in food, and

their disease manifestation in humans.

deals !ith substances found in food (contaminants) that

miht be harmful to those !ho consume sufficient

-uantities of the food containin such substances.

n#ol#es deli#erin a safe and edible supply of food to theconsumer.

25/05/2010 MohdKhan(c)2011


30/73

$ood Toxicology$ood Toxicology

$ood contaminanats%

% n#ironmental pollutants

< the air, !ater and soil, such as the case !ith toxic

metals, P0Bs (Polychlorinated Biphenyls) and dioxins,

% 1arious chemicals (intentionally used)

< pesticides, animal drus, antibiotics and other

arochemicals

< food additi#es.

% Toxins

< Plant, animal and microbial toxins

3125/05/2010 MohdKhan(c)2011


31/73

$ood Toxicology$ood Toxicology

human exposure to toxic chemicals and nutritional imbalances arecurrently "no!n or suspected to be responsible for promotin or

causin% cancer,

% "idney and li#er dysfunction,

% hormonal imbalance,

% immune system suppression,

% musculos"eletal disease,% birth defects,

% premature births,

% impeded ner#ous and sensory system de#elopment,

% reproducti#e disorders,

% mental health problems,

% cardio#ascular diseases,

% enitor2urinary disease,% old2ae dementia, and

% learnin disabilities.

3225/05/2010 MohdKhan(c)2011


32/73

33

utritional Toxicologyutritional Toxicology

3utritional toxicoloy is the study of the

nutritional aspects of toxicoloy.

% tarets the interrelations that toxicants or

toxins ha#e !ith nutrients in the diet, !hichaffect nutritional status and pre#ent aainst

the ad#erse effects of toxicants or toxins

% % antinutrient substances

25/05/2010 MohdKhan(c)2011


33/73

34

Clinical ToxicologyClinical Toxicology

s concerned !ith diseases and illnesses

associated !ith short term or lon term

exposure to toxic chemicals.

25/05/2010 MohdKhan(c)2011


34/73

35

Forensic ToxicologyForensic Toxicology

4elps to establish cause and

effect relationships bet!eenexposure to a dru or

chemical and the toxic or

lethal effects that result.

25/05/2010 MohdKhan(c)2011


35/73

36

!escripti"e Toxicology!escripti"e Toxicology

s concerned !ith

atherin toxicoloical

information from animalexperimentation.

% These type of experiments

are used to establish the

chemical dosae that!ould cause illness and

death.

25/05/2010 MohdKhan(c)2011


36/73

37

Mechanistic ToxicologyMechanistic Toxicology

5a"es obser#ations on ho! toxic

substances cause their effects.

25/05/2010 MohdKhan(c)2011


37/73

38

#nalytical Toxicology#nalytical Toxicology

dentifies the toxicant throuh analysis of

body fluids, stomach content, excrement,

s"in, or suspected containers.

25/05/2010 MohdKhan(c)2011


38/73

39

$egulatory Toxicology$egulatory Toxicology

6athers and e#aluates existin

toxicoloical information to establish

concentration2based standards of 7safe8exposure.

25/05/2010 MohdKhan(c)2011


39/73

40

egulatory Toxicologyegulatory Toxicology

+se data from descripti#e and mechanistic

toxicoloy to perform ris" assessments.

0oncerned !ith meetin re-uirements

of reulatory aencies.

ndustry/o#ernment interactions.

25/05/2010 MohdKhan(c)2011


40/73

41

.hat Do Toxicologists Do?.hat Do Toxicologists Do?

5ost toxicoloists !or" to de#elop

a mechanistic understandin of

ho! chemicals affect li#in

systems%% 9e#elop safer chemical products

% 9e#elop safer drus

% 9etermine ris"s for chemical exposures

% 9e#elop treatments for chemical

exposures% Teach ( e.. other toxicoloists,

raduate students, and youth)

25/05/2010 MohdKhan(c)2011


41/73

42

ha* Do Toxicoo!i'*' Do?ha* Do Toxicoo!i'*' Do?

5echanistic toxicoloists study ho! a chemical

causes toxic effects by in#estiatin its absorption,

distribution, metabolism and excretion (:95). Theyoften !or" in academic settins or pri#ate industries and

de#elop antidotes.

9escripti#e toxicoloists e#aluate the toxicity ofdrus, foods, and other products. They often performexperiments in a pharmaceutical or academic settin.

0linical toxicoloists usually are physicians or#eterinarians interested in the pre#ention, dianosis,

and treatment of poisonin cases. They ha#especiali;ed trainin in emerency medicine andpoison manaement.

25/05/2010 MohdKhan(c)2011


42/73

43

ha* Do Toxicoo!i'*' Do?ha* Do Toxicoo!i'*' Do?

$orensic toxicoloists study the

application of toxicologyto the la!. Theyuses chemical analysis to determine thecause and circumstances of death in apostmortem in#estiation.

n#ironmental toxicoloists study theeffects of pollutants on oranisms,populations, ecosystems, and thebiosphere.


43/73

44

+$,i$w+$,i$wToxicoloy is the science that studies the harmful effects of

o#erexposure to drus, en#ironmental contaminants, andnaturally occurrin substances found in food, !ater, air, andsoil.

% 5ain obecti#es are to establish safe doses and determinemechanisms of bioloic action of chemical substances.

: career in toxicoloy in#ol#es e#aluatin the harmful effectsand mechanisms of action of chemicals in people, otheranimals, and all other li#in thins in the en#ironment.

% This !or" may be carried out in o#ernment, pri#ateindustry and consultin firms, or uni#ersities and otherresearch settins.

Toxicoloists routinely use many sophisticated tools todetermine ho! chemicals are harmful.

(e..) computer simulations, computer chips, molecularbioloy, cultured cells, and enetically2enineeredlaboratory animals .

25/05/2010 MohdKhan(c)2011


44/73

,rinciples of o!icology,rinciples of o!icology

25/05/2010 45MohdKhan(c)2011


45/73

-undamental ules of o!icology-undamental ules of o!icology

xposure*ust (irst occur (or the che*ical to 2resent a

ris"8

The manitudeo( ris"is 2ro2ortional to both the potency

o( the che*ical and the extent of exposure8

0The dose ma"es the poison1 Ba*ount o( che*ical at the

target site deter*ines toxicityC8

4625/05/2010 MohdKhan(c)2011


46/73

Th$ Do'$Th$ Do'$

S4iss 2hysician

Paracelsus B;5)>&;C

%#ll substances are poisons& there is

none 'hich is not a poison. The right

dose di((erentiates a poison (rom a

remedy.)

4725/05/2010 MohdKhan(c)2011


47/73

he Dose /akes the ,oison0he Dose /akes the ,oison0

An a22arently non>toxic che*ical can be toxic at high

doses8 BToo *uch o( a good thing can be bad!C8

ighly toxic che*icals can be li(e saving 4hen given in

a22ro2riate doses8 BPoisons are not har*(ul at a

su((iciently lo4 doseC

4825/05/2010 MohdKhan(c)2011


48/73

25/05/2010 49

Do'$Do'$9etermines >hether a 0hemical >ill Be

Beneficial or Poisonous

4enecial Dose Toxic Dose

,spirin -00 /000 mg /000 -0000 mg

1itamin , 5000 units!day 50000 units!day

2xygen 30% (,ir) 50 40% (,ir)

MohdKhan(c)2011


49/73

LD12 omparisonLD12 omparison

5025/05/2010 MohdKhan(c)2011


50/73

&!posure&!posureonceptsoncepts

x2osure *eans 9ontact 4ith a ha@ard8< 4a;ard ?is a chemical substance, physical aent,

or bioloical aent that can harm the health ofpeople

Di((erent toxic res2onses *ay arise (ro*di((erent$% outes o( ex2osure8% Freuencies Bho4 o(tenC o( ex2osure8

% Duration Bho4 longC o( ex2osure Bacute vs8chronicC8

% 9oncentration o( ex2osure Bho4 *uchC >the DS

5isk 6 %a&ard x 7xpo

5125/05/2010 MohdKhan(c)2011


51/73

+ou*$ o- .xo'u%$+ou*$ o- .xo'u%$

Lngestion B4ater and (oodC

Absor2tion Bthrough s#inC

Ln:ection Bbite, 2uncture, or cutC

Lnhalation BairC

Peo2le can 2rotect the*selves by

bloc#ing these routes o( ex2osure8

5225/05/2010 MohdKhan(c)2011


52/73

/a3or outes of o!icant &ntry/a3or outes of o!icant &ntry

nestion ? #ia the astro2intestinal @6A tract

nhalation ? #ia the luns

9ermal ? #ia the s"in

&ther Parenteral (non2intestinal) routes%% ntra#enous (1) ? direct inection into a #ein

% ntraperitoneal (P) ? inection into the peritoneal ca#ity

% ubcutaneous (0) ? inection bet!een the s"in and the muscle

% ntramuscular (5) ? inection directly into the muscle

%ntradermal ? inection into the dermis

&ccupational xposures ? nhalation, 9ermal

:ccidental / uicide xposures ? nestion

5325/05/2010 MohdKhan(c)2011


53/73

+ou*$ o- .xo'u%$+ou*$ o- .xo'u%$

Lngestions account (or -57 o( ex2osures

% -7 der*al

% N7 o2hthal*ologic

% &7 inhalations

% )7 stings and bites

% '8)7 in:ection

Ty2ical ((ectiveness o( oute o(x2osure$

i, inha$ i i& in!$'* *oica

5425/05/2010 MohdKhan(c)2011


54/73

Du%a*ion %$u$nc" o- .xo'u%$Du%a*ion %$u$nc" o- .xo'u%$

Duration and (reuency are also i*2ortantco*2onents o( ex2osure and contribute todose8

Acute ex2osure > less than 6; hoursJusually entails a single ex2osure

e2eated ex2osures are classi(ied as$Subacute > re2eated (or u2 to )' days

Subchronic > re2eated (or )'>5' days

9hronic >re2eated (or over 5' days

5525/05/2010 MohdKhan(c)2011


55/73

ou%c$' o- .xo'u%$ou%c$' o- .xo'u%$

xposure to chemicals may come from

many sources%

% n#ironmental

% &ccupational

% Therapeutic

% 9ietary

% :ccidental

% 9eliberate

5625/05/2010 MohdKhan(c)2011


56/73

57

Mechanisms o( ToxicityMechanisms o( Toxicity

The ter* 7toxicity) is used to describe the nature o(adverse e((ects 2roduced and the conditionsnecessary (or their 2roduction8

=e(ore toxicity can develo2, a substance *ust co*einto contact 4ith a body sur(ace such as s#in, eye or*ucus o( the ali*entary or res2iratory tract % anex2osure8

25/05/2010 MohdKhan(c)2011


57/73

/echanisms of o!ic &ffects/echanisms of o!ic &ffects

Adverse e((ects can occur at the level o( the*olecule, cell, organ, or organis*

Molecular level$ che*ical can interact 4ith$ Proteins +"i2ids + D3A

9ellular level$ che*ical can% inter(ere 4ith rece2tor>ligand binding

% inter(ere 4ith *e*brane (unction% inter(ere 4ith cellular energy 2roduction% bind to bio*olecules% agitate ho*eostasis

5825/05/2010 MohdKhan(c)2011


58/73

/echanisms of o!icity/echanisms of o!icity

8 Lnter(ere 4ith 6trans2ort or tissue utili@ation o(

oxygen Bexa*2le cyanide, 9C

68 A((ect 93S Bexa*2le cocaine, sedativesC

)8 A((ect A3S Bexa*2le organo2hos2hatesC

;8 A((ect lungs Bexa*2le 2arauatC

&8 A((ect cardiovascular syste* Bexa*2le T9A, 9aOO

channel bloc#ersC

N8 Direct local da*age Bexa*2le acids, basesC

-8 Delayed e((ects on liver or #idneys Bexa*2le

aceta*ino2hen, *etalsC

5925/05/2010 MohdKhan(c)2011


59/73

ypes of to!ic effectypes of to!ic effect

: !ide #ariety of effects due to #arious toxicants%% :lleric aents$ itching, rashes, snee@ing, 4atery eyes8

% :sphyxiants$ cause dis2lace*ent o( oxygen and thus

su((ocation8% rritants$ cause 2ul*onary ede*a B(luid in the lungsC 4heninhaled at high concentrations and rashes 4hen s2illed ontothe s#in8

% 3ecrotic aents% cause cell death8

% 0arcinoens, mutaens and teratoens$9ancer, *utations,and de(or*ed e*bryos result (ro* chronic ex2osure to lo4levels

% ystemic poisons% can have an adverse e((ect on the 4holebody 4hen ta#en internally8

6025/05/2010 MohdKhan(c)2011


60/73

Ad'erse &ffectsAd'erse &ffects

3ot all orans are affected e-ually% greater susce2tibility o( the target organ

% higher concentration o( active co*2ound

i#er$ high blood (lo4, oxidative reactions

Cidney$ high blood (lo4, concentratesche*icals

un$ high blood (lo4, site o( ex2osure

3eurons$ oxygen de2endent, irreversibleda*age

5yocardium$ oxygen de2endent

Bone marro!, intestinal mucosa$ ra2iddivide

6125/05/2010 MohdKhan(c)2011


61/73

Ultimatum of o!ic &ffectsUltimatum of o!ic &ffects

9eath> arsenic,

cyanide

&ran 9amae >

o@one, lead 5utaenesis> UE light

0arcinoenesis>

ben@ene, asbestos

Teratoenesis>

thalido*ide

6225/05/2010 MohdKhan(c)2011


62/73

25/05/2010 63

$%c$*ion ,' +$ai*"$%c$*ion ,' +$ai*"

Perception%

% Pollution is a sinificant contributor to cancer

and that cancer rates are soarin.


63/73

25/05/2010 64

anc$% D$a*h +a*$' # Ma$anc$% D$a*h +a*$' # Ma$

MohdKhan(c)2011


64/73

25/05/2010 65

anc$% D$a*h +a*$' # $&a$anc$% D$a*h +a*$' # $&a$

MohdKhan(c)2011


65/73

25/05/2010 66

$%c$*ion ,' +$ai*"$%c$*ion ,' +$ai*"

Perception% 4ih dose animal cancer tests tell us the

sinificant cancer ris"s for humans.


66/73

25/05/2010 67

$%c$*ion ,' +$ai*"$%c$*ion ,' +$ai*"

Perception% 4uman exposures to carcinoens and other

toxins are nearly all due to synthetic

chemicals.


67/73

25/05/2010 68

$%c$*ion ,' +$ai*"$%c$*ion ,' +$ai*"

Perception% ynthetic toxins pose reater carcinoenic

ha;ards than natural toxins.


68/73

25/05/2010 69

$%c$*ion ,' +$ai*"$%c$*ion ,' +$ai*"

Perception

% Toxicoloy of man2made chemicals is different

from that of natural chemicals.


69/73

25/05/2010 70

$%c$*ion ,' +$ai*"$%c$*ion ,' +$ai*"

Perception

% 0orrelation implies causation.


70/73

25/05/2010 71

$%c$*ion' ou* h$&ica'$%c$*ion' ou* h$&ica'

>hat dri#es our perceptionsG

n#ol#es subecti#e udments.

:re chemicals badG% 3atural #s. synthetic

MohdKhan(c)2011


71/73

25/05/2010 72

:a*u%a a%cino!$n' in o--$$:a*u%a a%cino!$n' in o--$$

:cetaldehyde

Ben;aldehyde

Ben;ene

Ben;ofuran Ben;o@aApyrene

0affeic acid

0atechol

D,H,',I9iben;anthracene

thanol

thylben;ene

$ormaldehyde

$uran

$urfural

4ydroen peroxide

4ydro-uinone

imonine

tyrene

Toluene

Xylene

MohdKhan(c)2011


72/73

o!icology helps create a safero!icology helps create a safer

world ...world ... Toxicology is a (ascinating science that *a#es

biology and che*istry interesting and relevant8

Understanding . Bi8e8 *echanis*C so*ething

2roduces a toxic e((ect can lead to ne4 4ays o(2reventing or treating che*ically>related diseases8

Many diseases are the result o( an interactionbet4een our genetics Bindividual variabilityC andche*icals in our environ*ent8

Toxicology 2rovides an interesting and exciting4ay to a22ly science to i*2ortant 2roble*s o(social, environ*ental, and 2ublic healthsigni(icance8

7325/05/2010 MohdKhan(c)2011


73/73

Th$ .ndTh$ .nd

Concept and Principles of Toxicology (1)

Documents

Transcript of Concept and Principles of Toxicology (1)