Physiology research paper Example | Topics and Well Written Essays - 500 words

Physiology - Research Paper Example The researchers selected 128 children of patients with autosomal-dominant Alzheimer’s disease as study participants, as they were at risk of carrying the mutation. The autosomal-dominant nature of the disease in these cases was determined by family pedigrees. The mutations known in these pedigrees included presenilin 1, presenilin 2, and amyloid precursor protein. The expected age of symptom onset for the participants was set as the age at which the parent was diagnosed with Alzheimer’s disease. They studied several physiologic mechanisms occurring in these patients. First, they carried out clinical assessments of cognitive change using questionnaire-based scales, giving them a cognition score. This characterized the participants as normal cognitive function, very mild impairment, or mild impairment. Brain imaging with magnetic resonance imaging (MRI) was done to screen for any pre-existing brain disease. Positron emission tomography (PET) scanning was done to determine any regions of fibrillar amyloid deposition, and decreased metabolism. They also analyzed cerebrospinal fluid (CSF) for concentrations of tau, and beta-amyloid. They found that 50% of the asymptomatic study participants were carriers of the mutation for Alzheimer’s. The carriers had lower cognitive scores and at an earlier age, compared to non-carriers of the mutation. The carriers also developed bilateral hippocampal atrophy, seen on MRI, 15 years before expected symptom onset. Through PE scanning, they detected a selective decrease in the metabolism of the precuneus region of the brain in carriers, 10 years before expected symptom onset. Mutation carriers also had significant amyloid deposition in the precuneus region at 15 years before symptom onset, while non-carriers did not have any amyloid deposition there. Levels of CSF tau protein and plasma amyloid were elevated in the carriers 15 years before symptom onset,