人體生物化學(xué)與疾病-資料下載頁
2025-01-08 01:18本頁面
【正文】 en and 93% of patients in the database are caucasian.” ? Normally occurs in people between 40 to 70 years of age – Also can occur in people in their 20’s and 30’s From The ALS Association Cause of ALS ? Due to a mutation in SOD1, the superoxide radicals are not neutralized ? The radicals attack the motor neurons and degrade them ? Muscles are not able to be stimulated Symptoms of ALS ? First signs and symptoms (frequently overlooked) – Twitching and cramping of muscles (especially in hands and feet) – Stiffness – Weakness (especially in hands, arms and legs) – Slurred speech Picture taken from the National Institute of Aging Symptoms continued . . . ? Later signs and symptoms: – Difficulty chewing and swallowing – Shortness of breath – Muscle weakness due to wasting away of muscles ? Causes muscles to bee smaller – Respiratory failure – Paralysis Picture from the ALS Association ? This picture from the Neuromuscular website shows the wasting away of a person’s hands and arms ? Symptoms, or patterns of symptoms, are not the same for each ALS individual ? However, progressive muscle weakness and paralysis are universally experienced ? Since ALS attacks only motor neurons, the sense of sight, touch, hearing, taste, and smell are not affected ? Patients usually only live 3 to 5 years after they are diagnosed ? There are some cases。 however, where individuals have lived 10 or more years Diagnosing ALS ? 5,600 people in the US are diagnosed with ALS each year ? ALS is a very difficult disease to diagnose ? Blood tests, Urine tests, Spinal taps, xrays, muscle or nerve biopsies, or a neurological examinations are administered Picture from Medication for ALS ? Rilutek (brand name) / riluzole (generic) – slows progression of ALS – It is the only prescription drug for ALS – Approved in December 1995 From the MDA Publications Picture from Hypothesis ? The mechanisms that cause mutations in SOD1 that lead to ALS are unknown Hypothesis 1 ? An increase or a decrease in the activity of SOD1 may cause ALS – We theorized that a decrease, rather than an increase, may be the cause of ALS. – Theory: decrease = produces more harmful free radicals – We searched NCBI in support for both an increase and a decrease in SOD1 activity Support from NCBI ? One study conducted by Rosen found that increased levels of expression of SOD1 in mice would produce excessive levels of hydrogen peroxide From OMIM Picture from The ALS Society of Canada Support continued . . . ? According to Kunst overexpression of normal SOD1 accelerates disease onset and progression – However, a decrease or increase in SOD1 activity is not sufficient to cause ALS in mice From PubMed Hypothesis 2 ? SOD1 may lose its ability to bind zinc (Zn), Copper (Cu), or both – This may cause SOD1 to lose its ability to process free radicals From MDA Publications Support from NCBI ? Zinc and Copper = normal ? Zinc removed = toxic ? Zinc and Copper removed = nontoxic ? Copper removed = not studied yet ? Zinc that is bound to SOD1 may stabilize the protein From PubMed Support continued . . . ? Zincdeficient SOD1 produces more free radicals than it destroys ? SOD1 mutant can not bind zinc as strongly as normal SOD1
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號(hào)-1