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Toxicology > Toxicology - deck V > Flashcards

Toxicology - deck V Flashcards

1
Q

Although a number of food contaminants are suspected of causing human cancer, only
one substance group, conclusively do so.
What group?

A

Although a number of food contaminants are suspected of causing human cancer, only
one substance group, aflatoxins, conclusively do so.

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2
Q

Chronic aflatoxicosis that primarily happens in the case of domestic animals, but also humans, is characterized by

A

cholangial proliferation, periportal fibrosis, jaundice, liver cirrhosis, weight loss, and an
elevated sensibility to illnesses.

Long-term exposure of animals to low doses of ATB1 may lead to the formation of hepatome, cholangial, or hepatocellular carcinoma, and other malignant tumors.

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3
Q

Ochratoxins (OT) are a group of

A

four moderately stable derivatives of
isocoumarin linked amino acid phenylalanine, produced as secondary metabolites by the microfungi
A. ochraceus and P. verrucosum, contaminating barley, corn, wheat, oats, rye, green coffee beans, peanuts, grape juice and wine, beer, cocoa, dried fruits, and spices.

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4
Q

Mechanisms of ochratoxin toxicity (5)

A
  • inhibition of protein synthesis,
  • promotion of membrane peroxidation,
  • disruption of calcium homeostasis,
  • inhibition of mitochondrial respiration
  • DNA damage.
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5
Q

Zearalenone (ZEA) and zearalenol are

A

endocrine disrupters, synthesized by the Fusarium fungi , contaminating primarily corn, but also wheat, barley, oats, cassava, soy, sorgo, bananas, and other fruits.
ZEA (alias F-2 toxin), has been found also in beer.

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6
Q

Zearalenone metabolites are

A

estrogens, large amounts may cause infertility of both femal and male animals. Although the hog is the most sensitive animal, human contacts with ZA and metabolites are also harmful.

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7
Q

Fumonisins

A

are a group of mycotoxins produced by microfungi of the genus Fusarium.

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8
Q

The mechanisms behind both acute toxicity and carcinogenicity of fumonisins are

A

not clear yet.
Exposure to fumonisin has increased lipid peroxidation in the liver that plays an important role in the toxicity and carcinogenicity of fumonisins.

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9
Q

Trichothecenes are a group of

A

12,13-epoxytrichothecenes, produced on various cereal grains mainly by microfungi
of Fusarium such as F. poeae, F. tricinctum, etc. T-2 toxin, diacetylnivalenol, deoxynivalenol (DON or vomitoxin), HT-2 toxin, and others, altogether over 20 compounds.

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10
Q

Symptoms of Trichothecenes

A

complete atrophy of the bone marrow and thymus, agranulocytosis, necrotic angina,
sepsis, and hemorrhagic diathesis. Up to 80% fatal end.

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11
Q

Sterigmatocystin is

A

structurally related to aflatoxins and a precursor of aflatoxin B1, is produced by microfungi.

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12
Q

citreoviridin is a

A

Neurotoxin produced in yellow rice by Penicillium citreoviride.

Ingestion causes vomiting, convulsions, and paralysis of hind legs and sides of animals
followed by disorders in the functioning of the respiratory and cardiovascular systems,
general paralysis, fever, gasping, coma, and arrest of respiration.

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13
Q

From history, serious acute ergot intoxications or ergotisms are known, appearing after consumption of

A

grain (particularly rye) contaminated with microfungi.

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14
Q

ergot alkaloids are derivatives of

A

lysergic acid

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15
Q

name 3 ergot alkaloids

A

ergotoxin, ergotamine, ergomethrine and others, altogether about 50 different compounds.

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16
Q

form of the ergotism can develop,
depending on the proportion of various ergot alkaloids in the food. name the forms

A

Either gangrenous or convulsive (CNS)

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17
Q

Related to the ergot alkaloids is a semisynthetic narcotic

A

diethylamide of lysergic acid (LSD) that in addition to its psychogenic properties (hallucinations, delusions) is also mutagenic and embryotoxic.

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18
Q

explain Combined toxicity of mycotoxins

A

Feeds or foodstuffs of plant origin may simultaneously contain several mycotoxins originated either from one or several molds.

The effects can combine. If similar action mechanism, result can be additive, if diferent mechanisms, result can be either synergic or antagonistic (not always).

Most of experimental results are connected with Ochratoxin A (bioweapon!!).

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19
Q

what is phytanic acid

A

Phytanic acids are medium (6-12 carbon atoms), branched chain fatty acids that humans obtain by eating Dairy products & animal fats, as they are not naturally produced by the human body.

If they accumulate in the body they can cause many tissues neurological symptoms like reduced physical and mental growth, blindness and deafness appear.

They can accumulate in ppl who have a genetic disease which causes them to lack the appropraite enzymes for its degradation.

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20
Q

Refsum disease

A

Phytanic acid accumulation most commonly occurs when an individual has Refsum disease, a rare inherited neurologic disorder characterized by numbness or weakness in the arms and legs.

Accumulation of phytanic acid occurs because of a lack of a certain enzyme required for its metabolism.

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21
Q

phycotoxins are

A

Toxic compounds produced by sea phytoplankton or alga.

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22
Q

TTX is

A

Tetrodotoxin is an extremely poisonous substance (acutely 10,000 times more toxic than CN- ion), found in various terrestrial and marine animals (frog skin, octopus, puffer fish etc.).

Tetrodotoxin is an extremely potent heat-stable nerve toxicant, a specific blocker of Na channels of the skeletal
muscles.

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23
Q

ciguatoxin is?

A

Ciguatera fish toxin or ciguatoxin (CTX) are caused by consumption of fish inhabiting the tropical coral riffs between 35° of north and south latitudes, especially in the Caribbean Sea, but also in the Atlantic and Pacific Oceans.

seriously toxic to humans.

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24
Q

the most common nonbacterial fish-borne
poisoning in the US

A

is CTX poisoning, ciguatoxin

seriously toxic to humans.

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25
Q

Toxicity of shellfish is proportional to the

A

the concentration of algae in water and disappears over 2 weeks after the disappearance of the toxic phytoplankton.

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26
Q

Shellfish poisonings are divided into four groups

A

paralytic,
diarrhetic,
neurotoxic, and
amnesic.

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27
Q

Paralytic shellfish poisoning (PSP) is caused by

A

more than 20 structurally related imidazoline-guanidinium alkaloids, produced by a number of sea dinoflagellates (single-celled eukaryotes
considered to be algae), and linked to them, cyanobacteria swallowed and accumulated

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28
Q

Name one of the most well-known causative agents of Paralytic shellfish poisoning

A

saxitoxins produced by the cyanobacteria and dinoflagellates

others are, anatoxins and gonyautoxins

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29
Q

Anatoxins are a group of

A

low-molecular neurotoxic alkaloids that were first found in freshwater blue alga Anabaena flos-aquae.

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30
Q

name an Acidic Diarrethic shellfish poisoning toxin

A

okadaic acid

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31
Q

name a neutral Diarrethic shellfish poisoning toxin

A

pectenotoxins

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32
Q

brevetoxins A, B and C are

A

lipophilic and heat-stable polyether nerve poisons produced by dinoflagellates

they are toxic to fish but not to shellfish

they cause mass death of fish and contaminated shellfish eating people sick.

Although brevetoxins are capable of killing the test animals in the case of different routes of
administration, including peroral, no human deaths have been described.

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33
Q

Amnesic shellfish poisoning (ASP) is originally from

A

red algae

the toxin is eaten by krill, which in turn is consumed by whales and other sea animals as well as birds.

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34
Q

Microcystins and nodularins are produced by

A

freshwater blue algae (cyanobacteria)

More than 50 various microcystin heptapeptidic congeners are known. They are both specific hepatic toxicants and carcinogens.

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35
Q

what organ is especially sensitive to the toxic effect of microcystins and nodularins.

A

liver

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36
Q

Human poisoning by microcystins and nodularins
can be caused by

A

eating of fish or shellfish contaminated with these toxins.

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37
Q

The first man-made pesticide known from the history was

A

sulphur, the smoke of which was used for protection of crop plants in the ancient China already 3,000 years ago.

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38
Q

In the 16th century, Chinese repelled insects with very omnitoxic

A

arsenic.

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39
Q

In the 17th century, what (2) were used to protect agricultural plants against rodents.

A

In the 17th century, tobacco leaves (agent nicotine) and the seeds of the strychnine tree were used to protect agricultural plants against rodents.

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40
Q

In the mid-19th century, what 2 compounds were used as insecticides.

A

In the mid-19th century, rothenon from the roots of Derris eliptica and pyrethrum from the blossoms of chrysanthemum were used as insecticides.

41
Q

The epoch of synthetic pesticides started when with what?

A

The epoch of synthetic pesticides started in 1939 with DDT.

42
Q

At present, the most important groups of pesticides are: (3)

A
  • Insecticides (against pestiferous insects)
  • Herbicides (against weeds)
  • Fungicides (against unwanted microfungi or molds)
43
Q

what are mite killing compounds called

A

Acaricides to kill mites

44
Q

what are meatode killing compounds called

A

nematocides to kill nematodes

45
Q

Pesticides are used in various forms and by various methods such as (4)

A

– by dusting as powder,
- by spraying of solution,
- as a smoke, or
- by furrow irrigation.

46
Q

To keep the content of pesticide residues in food and feed plant as low as possible, it is very
important to strictly follow the instructions of pesticide handling, including (2)

A

consideration of the waiting period between the last usage and harvesting,
use of minimal possible doses, and so forth.

47
Q

According to the chemical structure, pesticides can be divided into groups (2)

A
  1. Inorganic.
  2. Organochlorine compounds.
48
Q

organochlorines are a

A

group of pesticides.

Toxicity to mammals low, biomagnification high,
biodegradation slow.

49
Q

DDT and its main metabolite DDE are very toxic to fish and birds by

A

endocrine disruption mechanisms.

50
Q

DDT like other lipophilic toxicants that are deposited in the adipose tissue has no biologic effect

A

as long as the volume of the tissue does not decrease, for example, because of starvation or intensive physical activities.

produces no known toxic effects while it is stored

51
Q

Organophosphorus compounds are essentially more toxic than

A

organochlorine pesticides, although less toxic than their military prototypes.

Some of them, which are relatively safe to humans, are used as insecticides.

Phosphoric acid esters are acutely neurotoxic to mammals, inhibiting the acetylcholinesterase-catalyzed hydrolysis of the neurotransmitter acetylcholine in synapsis. Acetylcholine, accumulated due to this inhibition, causes permanent nerve excitation.

52
Q

Recent research has revealed a wide variety of human health problems like diabetes mellitus caused by exposure to

A

Organophosphorus pesticides considered as a major food chain contaminant.

53
Q

acute Organophosphorus compound/pesticide poisoning is caused first of all by

A

inhibition of cholinesterase in mammals,

then in sub-chronic or chronic exposition induction of oxidative stress has been reported as the major mechanism of OP toxicity.

Thus, Supplementation with natural or synthetic antioxidants may be beneficial in OP poisoning.

54
Q

Phosphoric acid esters cause about 3,000 agricultural intoxications yearly, the most toxic of
them is

A

parathion.

malathion is considerably less poisonous.

Very often, these compounds have a smell of garlic, which simplifies diagnosis of the poisonings

55
Q

Carbamates are used against insects that have a resistance against

A

organophosphorus compounds.

56
Q

One of the most toxic carbamates is

A

aldicarb

The carbamates Aldicarb, carbofuran, methomyl, and propoxur are classified as probable human
carcinogens.

57
Q

Pyrethroids are

A

esters of chrysanthemic acid synthetic formulations, similar to pyrethrum – an efficient contact poison of insects from the blossoms of pyrethrum daisy.

Some fish, shellfish, and useful insects are very sensitive to the adverse effects of pyrethroids.

58
Q

Herbicides are divided into two groups – compounds with ? and ?

A

– compounds with a broad effect and selective effect.

59
Q

Herbicides Are used mainly in grain farming to kill

A

the weeds already at the start of the vegetation period.

Their toxic action is directed to the disruption of metabolism, e.g. through blocking of photosynthesis.

60
Q

The problem of herbicide residues in food is happily negligible; toxicity of most herbicides in
warm-blooded organisms is

A

low, no case of dietary intoxication by herbicides is known at a normal use of these compounds.

However, the negative effect of herbicides to soil microflora and arthropoda cannot be ignored.

61
Q

Most herbicides do not accumulate in the environment; most of them contain no highly
toxic additives.

Exceptions are

A

toxic nonselective pyridines paraquat (PQ) and diquat (DQ), which are used for liquidation of all vegetation on a surface.

62
Q

Paraquat is

A

a very effective toxic herbicide with a broad spectrum of activity. oisonous to higher organisms and a well-characterized pneumotoxicant.

destroys all green plant tissues by interfering with the intracellular electron transfer systems, thereby inhibiting reduction of NADP to NADPH during photosynthesis.

63
Q

PQ generates

A

Paraquat generates free radicals.

It leads to the formation of ROS, such as superoxide anion, singlet oxygen, as well as hydroxyl and peroxyl radicals.

64
Q

According to the recommendation 19/5 of HELCOM and Stockholm Convention of Persistent Organic Pollutants (POP), the use of a number of the so-called

A

aged pesticides (including all organochlorine) as biocides and plant protectives will be stopped and all the leftovers must be destroyed.

Maybe from this list, at least DDT should have been left out, which obviously is not toxic to humans and, in case of reasonable use, also to fish and birds.

Regrettable are the cases of public anti-DDT hysteria without any assessment of the correct scientific data.

65
Q

The ways of production of collective poisoning by pesticides are: (3)

A
  • Occupational exposure (of people working in pesticide manufacture and application as well as crop management
  • Cutaneous contact
  • Contamination of foods
66
Q

Over ?% of foods in EU contain pesticide residues within legal limits

A

Over 97% of foods in EU contain pesticide residues within legal limits.

67
Q

It is possible to distinguish four groups of dietary epidemics caused by pesticides:

A
  • Contamination of food during transport or storage.
  • Ingestion of seed prepared for sowing.
  • Accidental use of pesticides in food preparation because of their organoleptic similarity to foodstuffs.
  • Presence of pesticides in water or food due to unsafe use of pesticides.
68
Q

Glyphosate is a

A

broad-spectrum systemic OP herbicide used to kill
weeds, particularly annual broadleaf weeds and grasses around the world.

Initially patented and sold by Monsanto Company in the 1970s under the tradename Roundup, US patent expired in 2000

69
Q

Glyphosate inhibits an

A

enzyme involved in the synthesis of the aromatic amino acids - tyrosine, tryptophan and phenylalanine.

Because of this mode of action, it is only effective on actively growing plants; but ineffective as a pre-emergence herbicide.

70
Q

MRL

A

Maximum residue limits (MRL in mg/kg or μg/kg of raw foodstuff) have been established by the EU and Codex Alimentarius Commission for veterinary drug compounds allowed to be used as drugs.

Legislatively, respective withdrawal periods during which pre-slaughtering administration of a drug is prohibited as well as respective systems of control and screening are built up

71
Q

The most notable recent “epidemy” of allergic reactions caused by a veterinary drug in meat involved consumption of beef containing residues of the

A

illegal growth promoter, clenbuterol.

Anaphylactic reactions have been reported to result from consumption of beef or pork containing penicillin residues.

72
Q

Active antibiotic residues are not possible to remove or to render them harmless in raw food of animal origin
since

A

most antibiotics are resistant to pasteurization and other types of heat treatment.

73
Q

The most widely used antibacterial drug is

A

benzylpenicillin (penicillin G).

74
Q

which two antibiotics have exerted carcinogenicity

A

Sulfonamide and nitrofuran antibiotics have exerted carcinogenicity.

nitrofurans use has been banned in the EU.

75
Q

EU drug residue monitoring programs prescribe analysis of
nitrofurans as well as sulfonamides, penicillins, tetracyclins,
fluoroquinolons, macrolides, and other antibiotics in the raw food material of animal origin.

First, random samples of meat, milk, eggs, and so forth are analyzed by

A

the microbiological agar-diffusion method.

  • Thereafter the samples that prove to be positive are subjected to a chromatographic analysis to confirm and quantify the particular antibiotic.
76
Q

A special issue is highly toxic chloramphenicol (CAP) to which most

A

aerobic and practically all the anaerobic bacteria are sensitive.

CAP causes aplastic anemia, bone marrow suppression, and
liver damage. As a mutagen, CAP increases the risk of
childhood lymphoblastic leukemia.

EU has, since 1994, prohibited the use of CAP in the case
of productive animals, including honeybees.

Manufacturing of oral CAP was stopped in the US in 1991.
In 2007, China announced prohibition of CAP as a
veterinary drug. However, CAP is still abused and its residues have been found in various food samples, such as muscle, shrimp, milk, and honey

77
Q

Hormones as anabolic chemical regulators of physiogical processes are used analogically to antibiotics

A

as growth stimulators of agricultural animals.

78
Q

According to their chemical structure, hormones are divided into three main groups –

A

proteins, peptides and steroids.

Since proteins and peptides are decomposed during digestion, these groups cannot have an essential toxicological value in humans.

79
Q

Steroidal hormones are stable in the

A

digestive tract; they are well absorbed, and maintain their
effect until metabolized into inactive compounds.

80
Q

synthetic substances with an analogical activity to natural hormones like testosterone and estradiol (5)

A

synthetic substances with an analogical activity such as esters of estradiol and testosterone, trenbolone,
diethylstilbestrol (DES) and zeranol.

81
Q

In the EU, the use of all steroidal hormones in ? cattle breeding is prohibited.

A

In the EU, the use of all steroidal hormones in cattle breeding is prohibited.

While natural hormones are not expected, due to their short half-life, to have adverse effects in food, synthetic hormones are much more stable in the organism.

82
Q

Food additives are compounds that are

A

intentionally added to food for improvement of its various characteristics, may raise specific toxicological concerns.

83
Q

3 examples of Food additives used for centuries

A

Sodium chloride, acetic acid or various spices

84
Q

a purposeful addition of various compounds to food has become really extensive, with about ? food additives used globally.

A

2,500 !! food additives used globally.

85
Q

to keep track of food addivtives in europe, every approved food additive has a

A

so-called E-number.

In the unified scheme, many food additives not officially confirmed in Europe but allowed, for example, in the US or Australia or anywhere else also have, with the help of Codex Alimentarius Committee, the numbers.

86
Q

GRAS

A

generally recognized as safe

87
Q

Food additives are divided based of thier sources, into three main groups:

A
  1. Substances, isolated from edible plants or from other living material (e.g. lecithin, pectin)
  2. Substances, contained in foodstuffs (e.g.vit C)
  3. Substances not found in nature and obtained only synthetically (sweetener saccharin)
88
Q

In the system of the E-numbers, the additives have been divided into classes according to

A

the main purpose of their use.

89
Q

3 E-substances better to avoid

A
  • synthetic azo-dyes
  • Glutamates (maybe?)
  • synthetic sweeteners
    (aspartame, saccharine and others).
90
Q

Synthetic (azo) dyes are

A

toxic substances

Comet-test has shown that of all food additives food dyes are most genotoxic

91
Q

Na-glutamate (E621) is a

A

widely used food additive that is added to versatile meat and fish products, sausages, marinades, sauces, bouillon cubes, aroma salt.

Controversial opinions on glutamate safety.

92
Q

Na-glutamate provides the foods unique what?

A

unique 5-th taste (umami).

93
Q

Small amounts of glutamate combined with reduced amounts of table salt enable

A

using less salt for preparation of food.

94
Q

Glutamate is one of the most studied

A

food components and recognized as safe.

UN FAO and WHO have listed glutamate in the group of most safe food additives.

Regardless widespread belief about glutamate as a causing agent of asthma, migrain, headache and Chinese Restorant Syndrome (CRS), there is no firm clinical results to approve it.

95
Q

name 4 Synthetic sweeteners:

A

Sachharine (E 954)
Cyclamate (E 952)
Aspartame (E 951)
Sucralose (E 955)

96
Q

Sachharine (E 954) is 500 times sweeter than

A

saccharose.

Carcinogenicity suspected.

97
Q

Cyclamate (E 952) is 30-50 times sweeter than

A

saccharose. May cause photodermatitis,
cancer in combination with saccharine, banned in the USA and UK.

98
Q

Sucralose (E 955) is 1000 times sweeter than

A

saccharose. Very stable. ADI – 9 mg/kg/day.

Displaces aspartame. Splenda-trade name.

99
Q

Artificial sweeteners, which many people with weight issues use as a substitute for sugar, may increase the risk of developing

A

type 2 diabetes, according to a research.

Toxicology (6 decks)

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