Lead Flashcards
what are some household exposure things for lead
paint, dust, dyes, ceramine glazes
what is a major route of lead for most of the population
food and water, maybe air
what is a main thing that Pb does to blood
interferes with heme synthesis
what are 2 things that are sensitive to Pb with heme
delta-aminolevulinic acid dehydratas (ALAD) and ferrochelatase
what are 2 results with Pb inhibiting ALAD and ferrochelatase
depressed hematocrit/ RBC and anemia
what happens in severe Pb cases with anemia
RBCs end up with protophorphyrin chelated to zinc instead of hemoglobin chelated to iron
what does ferrochelatase do
catalyzes the insertion of iron into the protoporphyrin ring to form heme
what does ALAD do
joins 2 ALA units to form porphobilinogen
where does 2 ALA join via ALAD to become porphobilinogen
outside of the cell
what happens once porphobilinogen is made
it gets into the cell, mitochondria, some steps then you get protoporphyrin which should become heme
how does PB inhibit heme synthesis (where in the pathway)
blocks ALAD and ferrochelatase
what is a physical way to see if someone has lead poisoning
burtons line
what is burtons line
bluish purple line at the interface of gums and teeth
why do you get burtons line with lead
reaction with lead with sulphur ions released by oral bacteria resulting in lead sulphide deposition
what can make burtons line thicker
bad oral hygiene
what is 1 main thing that pb does in children
encephalopathy
what are some things that happen before coma and death with lead in children
lethargy, vomiting, ataxia, reduced consciousness
how can lead in children cause edema
extravasations of fluid from brain capillaries
what can happen to brain cells with lead in children
loss of neuronal cells and increase in glial cells
what is recovery accompanies by with lead in children
epilepsy, blindness, decreased IQ and cognition
what parts of the brain are affected with lead in children
prefrontal cortex, hippocampus, cerebellum
what is the classic symptom of pb neurotoxicity in adults
peripheral neuropathy
what kind of symptoms are seen with people that use lead based paints
footdrop and wristdrop movements (Lose control of extending wrist, ankles)
what is neuropathy characterized by in Pb neuropathy in adults
segmental demyelination and axonal degeneration
what is the main mechanism that Pb causes neurotoxiciry
mimics Ca++ so it interferes with many calcium related cellular processes
what does Pb do to glutamate NMDA receptors + effect
antagonist so Ca++ cannot enter the cell
glutamate receptors involved in learning or memory
what does Pb do to voltage gated calcium channels
inhibits (potently)
what does Pb do to PKC
stimulates it at picomolar concentrations
what does Pb do to cell death + how
induces apoptosis (accumulation of lead in mitochondria increases ETC and superoxide levels)
what does Pb do to hippocampus
reduces new neuron survival in hippocampus
where does Pb reduce new neuron survival
in hippocampus
what does Pb do to BBB endothelial cells
impairs them so the barrier becomes leaky due to claudin-1 depletion
what is claudin-1
protein involved in tight junctions
what does Pb do to oxidative stress
causes it
what does Pb do to GSH
depletion
