Acetylcholine and serotonin brain neurons can degenerate {Alzheimer's disease} {Alzheimer disease}, with intracellular tangled protein fibers {neurofibrillary tangle} and extracellular protein amyloid plaques.
plaque
Amyloid plaques can disrupt calcium regulation, create free radicals, or attract microglia. Presenilin gene makes gamma-secretase, which cuts cell-membrane protein {amyloid-beta precursor protein} (APP) inside membranes, and beta-secretase {secretase} cuts APP outside membranes, to make short A-beta proteins, which can be signal proteins. A-beta proteins can link hydrophobic ends to form plaques. Apolipoprotein E {apolipoprotein} (APOE-4) helps A-beta protein form plaques and slows A-beta protein removal. APP gene is on chromosome 21.
incidence
In USA, five million people have Alzheimer's disease. At age 60, 1 in 10,000 people develops Alzheimer's disease. By age 85, one in three people have dementia, typically Alzheimer's disease.
causes
Gene {presenilin gene} mutations can cause early-onset inherited Alzheimer's disease.
Apolipoprotein-E-gene isotype can modulate familial and sporadic Alzheimer's disease onset age.
Proteins {tau protein} can bind to tubulin, change, and increase in Alzheimer's disease. Tau proteins then make helical pairs, disrupting tubulin binding and microtubules.
Small proteins {amyloid beta-derived diffusible ligand} (ADDL) can come from amyloid-beta precursor proteins, can diffuse, do not make plaques, and attach to neuron receptors.
Brain proteins {clusterin} can increase in Alzheimer's disease.
Brain or brain blood-vessel degeneration {dementia}| {senile dementia} can be chronic and progressive.
symptoms
Recent-event memory loss is first symptom. People have intellect, memory, and personality impairment, but no consciousness or basic-skill impairment. People have unreal and slow thinking. People have slowness of, and disinterest in, activity. People forget goals, do not compensate for changes, live in present only, are emotionally sensitive, and are susceptible to bulbar palsy. At end, people lose basic personality and social skills.
causes
About 10% of older dementia patients have benign brain tumors and hypothyroidism.
types
Subnormality, old-age dementias, and remitting and relapsing psychoses are milder. Acute, primary, and curable dementias are harsher. Chronic, secondary, and incurable dementias are harsher.
recovery
Dementia reverses in 10% of patients.
Tau-protein buildup causes slowly developing dementia {Pick's disease} {frontotemporal dementia} in people 50 to 60 years old.
Repeated closures of small or large blood vessels, as in minor or major strokes, causes brain-cell loss {multi-infarct dementia}.
After pneumonia, heart attack, or hypothermia, older people can enter delirious states {pseudodementia}. Antidepressants reduce pseudodementia.
Old-age organic psychosis {senility}| can involve memory loss and poor thinking ability.
4-Medicine-Disease-Kinds-Organ-Nerve
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Date Modified: 2022.0225