Environment and diseases Flashcards
What are the diseases caused by the environment?
Diseases that are associated with exposure to exogenous chemical or physical agents (workplace, for example)
What is the mechanism behind diseases caused by the environment?
1) Exposure
2) Absorption at the portals of entry (inhalation, ingestion, or skin contact)
3) Distributed in the body, becomes:
- More toxic
- Less toxic
- Conjugated with products
4) Interacts with macromolecules (proteins, DNA, RNA, and receptors)
5a) They could be turned over and repaired then excreted or:
5b) Have a toxic effect on the body (genetically, carcinogenically, reproductively, and immunotoxicity)
What is the most important carcinogen found I tobacco smoke? and which organ does it affect?
Polycyclic aromatic hydrocarbon, which affects the lungs and the larynx
What are the carcinogenic metals found in cigarettes?
1) Arsenic
2) Nickel
3) Cadmium
4) Chromium
5) Acetaldehyde (tumor promoter)
6) Nitrogen dioxide (Irritants)
7) Hydrogen cyanide and CO (cilia toxins)
How is ethanol metabolized?
1) converted to acetaldehyde (by both alcohol dehydrogenase in the gastric mucosa and liver and by cytochrome P-450 “CYP2E1” in the liver)
2) Acetaldehyde is then converted into acetic acid via aldehyde dehydrogenase
Why do woman have higher levels of alcohol in their blood provided that they drink the same amount?
Because they have lower levels of gastric dehydrogenase
What is the most important disease caused by ethanol abuse?
Thiamine deficiency, can cause korsakoff syndrome and peripheral neuropathy that affects the nervous system
What is the effect of ethanol abuse on the liver?
1) Fatty liver
2) Acute alcoholic hepatitis (inflammation + fatty liver)
3) Liver cirrhosis (with chronic use)
by:
- Increased catabolism of fat by peripheral tissue and their delivery to the liver
- oxidation of fatty acids by mitochondria is decreased
- Acetaldehyde forms adducts with tubulin and impairs the function of microtubules, resulting in decreased transport of lipoproteins from the liver
What are the features of liver cirrhosis?
Irreversible
Regeneration
Fibrosis
Loss of architecture
- Characterized by the formation of micronodules of regenerating hepatocytes surrounded by dense collagen bands.
What are the features of acute hepatitis?
Reversible
1) Hepatocyte ballooning (a form of apoptosis)
2) Mallory-Denk bodies (intermediate filaments visible as eosinophilic cytoplasmic inclusions in degenerating hepatocytes)
3) Neutrophil infiltration
Which type of radiation is bad and should be avoided?
Radiation is energy distributed across the electromagnetic spectrum as waves or particles
- The waves are bas (Short wavelength + High frequency) and UV, as they can ionize biological target molecules and eject electrons
What type of radiation dose is used in radiotherapy for cancer patients?
intermediate doses, as they are capable of killing proliferating cells
What are the effects of ionizing radiation?
They damage the DNA which can be repaired or worse causes:
1) Cell death
2) Fetus/germ cell teratogenesis
3) Carcinogen
How can radiation cause cancer?
it can cause squamous cell carcinoma, basal cell carcinoma, and possible melanoma, especially in elderly and fair-skinned individuals, via the formation of pyrimidine dimer in DNA which could be repaired by nucleotide excision repair (NER)
