Huntingtons Disease Essays - Huntingtons Disease, Senescence, DNA

Huntingtons Disease Huntington's Background Huntington's disease is inherited as an autosomal dominant disease that gives rise to progressive, elective (localized) neural cell death associated with choreic movements (uncontrollable movements of the arms, legs, and face) and dementia. It is one of the more common inherited brain disorders. About 25,000 Americans have it and another 60,000 or so will carry the defective gene and will develop the disorder as they age. Physical deterioration occurs over a period of 10 to 20 years, usually beginning in a person's 30's or 40's. The gene is dominant and thus does not skip generations. Having the gene means a 92 percent chance of getting the disease. The disease is associated with increases in the length of a CAG triplet repeat present in a gene called 'huntington' located on chromosome 4. The classic signs of Huntington disease are progressive chorea, rigidity, and dementia, frequently associated with seizures. Studies & Research Studies were done to determine if somatic mtDNA (mitochondria DNA) mutations might contribute to the neurodegeneration observed in Huntington's disease. Part of the research was to analyze cerebral deletion levels in the temporal and frontal lobes. Research hypothesis: HD patients have significantly higher mtDNA deletionlevels than agematched controls in the frontal and temporal lobes of the cortex. To test the hypothesis, the amount of mtDNA deletion in 22 HD patients brains was examined by serial dilution-polymerase chain reaction (PCR) and compared the results with mtDNA deletion levels in 25 aged matched controls. Brain tissues from three cortical regions were taken during an autopsy (from the 22 HD symptomatic HD patients): frontal lobe, temporal lobe and occipital lobe, and putamen. Molecular analyses were performed on genomic DNA isolated from 200 mg of frozen brain regions as described above. The HD diagnosis was confirmed in patients by PCR amplification of the trinucleotide repeat in the IT 15 gene. One group was screened with primers that included polymorphism and the other was screened without the polymorphism. After heating the reaction to 94 degreesC for 4 minutes, 27 cycles of 1 minute at 94 degreesC and 2 minutes at 67 degreesC, tests were performed. The PCR products were settled on 8% polyacrylamide gels. The mtDNA deletion levels were quantitated relative to the total mtDNA levels by the dilution-PCR method. When the percentage of the mtDNA deletion relative to total mtDNA was used as a marker of mtDNA damage, most regions of the brain accrued a very small amount of mtDNA damage before age 75. Cortical regions accrued 1 to 2% deletion levels between ages 80-90, and the putamen accrued up to 12% of this deletion after age 80. The study presented evidence that HD patients have much higher mtDNA deletionlevels than agematched controls in the frontal and temporal lobes of the cortex. Temporal lobe mtDNA deletion levels were 11 fold higher in HD patients than in controls, whereas the frontal lobe deletion levels were fivefold higher in HD patients than in controls. There was no statistically significant difference in the average mtDNA deletion levels between HD patients and controls in the occipital lobe and the putamen. The increase in mtDNA deletion levels found in HD frontal and temporal lobes suggests that HD patients have an increase mtDNA somatic mutation rate. Could the increased rate be from a direct consequence of the expanded trinucleotide repeat of the HD gene, or is it from an indirect consequence? Whatever the origin of the deletion, these observations are consistent with the hypothesis: That the accumulation of somatic mtDNA mutations erodes the energy capacity of the brain, resulting in the neuronal loss and symptoms when energy output declines below tissue expression thresholds. (Neurology, October 95) Treatments Researchers have identified a key protein that causes the advancement of Huntington's after following up on the discovery two years ago of the gene that causes this disorder. Shortly after the Huntington's gene was identified, researchers found the protein it produces, a larger than normal molecule they called huntingtin that was unlike any protein previously identified. The question that they did not know was what either the healthy huntingtin protein or its aberrant form does in a cell. Recently, a team from Johns Hopkins University found a second protein called HAP-1,

Answers for ESL Learners

Answers for ESL Learners What are Adjectives? Adjectives are words that describe objects, people and places. She has a fast car. - Fast  describes the car.Susan is very intelligent.- Intelligent  describes Susan.Thats a beautiful mountain. - Beautiful describes mountain. In other words, adjectives describe characteristics of different things.   There are nine types of adjectives which are explained below. Each type of adjective includes a link to further details of the particular grammar usage. Descriptive Adjectives Descriptive adjectives are the most common type of adjective and are used to describe a certain quality such as large, small, expensive, cheap, etc. of the object. When using more than one descriptive adjective, it is important to make sure that they are placed in the correct  adjective order. Jennifer has a difficult job.That sad boy needs some ice cream.Susan purchased an expensive car. Proper Adjectives Proper adjectives are derived from  proper nouns  and must always be capitalized. Proper adjectives are often used to show the origin of something. Proper adjectives are also often the name of a language or a people.   French tires are excellent.Italian food is the best!Jack prefers Canadian maple syrup. Quantitative Adjectives Quantitative adjectives show us how many of something is available. In other words, numbers are quantitative adjectives. However, there are other quantitative adjectives such as  several, many, a lot of  which are also known as  quantifiers. There are two birds in that tree.She has many friends in Los Angeles.I count sixteen mistakes on your homework. Interrogative Adjectives Interrogative adjectives are used to ask questions. Interrogative adjectives include which and what. Common phrases using interrogative adjectives include:  Which type / kind of and what type / kind of plus a noun.   Which kind of car do you drive?What time should I come?What type of ice cream do you like? Possessive Adjectives Possessive adjectives  are similar to subject and object pronouns, but they indicate possession.  Possessive adjectives include my, your, his, her, its, our, and their.   My house is on the corner.I invited their friends to dinner.Her dog is very friendly. Possessive Nouns Possessive nouns act like possessive adjectives but are formed by using a noun.  Possessive nouns are created by adding an apostrophe to a noun to indicate possession such as the  cars color, or the  friends vacations. Toms best friend is Peter.The books cover is misleading.The houses garden is beautiful. Predicate Adjectives Predicate adjectives are placed at the end of a sentence or clause to describe the noun at the beginning of a sentence. Predicate adjectives are often used with the verb to be. His job is stressful.The vacation was enjoyable.It probably isnt very easy. Articles Definite and indefinite articles  can be thought of as a type of adjective because they describe the noun as one of many or a specific instance of a particular object.  Ã‚  A  and  an  are indefinite articles,  the  is the definite article. Tom would like an apple.She wrote the book thats on the table.I ordered a glass of beer. Demonstrative Pronouns Demonstrative pronouns  show which objects (noun or noun phrase) is meant. Demonstrative pronouns include  this, that, these  and  those.  This  and  that  are singular demonstrative adjectives, while these and those are plural. Demonstrative pronouns are also known as  determiners. I would like that sandwich for lunch.Andrew brought these books for everyone to read.Those trees are beautiful! Adjectives Quiz Find the adjective and  identify its form. Choose from: descriptive adjectiveproper adjectivequantitative adjectiveinterrogative adjectivepossessive adjectivepossessive nounpredicate adjectivedemonstrative pronoun I gave the ball to her cousin.Education is important.They have a beautiful daughter.Which kind of car did you decide to buy yesterday?Those cars belong to Peter.She has a lot of friends in China.Chicago is amazing!Jennifer proposed an elegant solution to the problem.What kind of grades did you get?Helens house is located in Georgia.  Italian food is the best!Holidays can be boring at times.  Alex has three books.Its a hot day.Our friend didnt answer the question. Answers: her - possessive adjectiveimportant - pronominal adjectivebeautiful - descriptive adjectivewhich kind of - interrogative adjectivethose - demonstrative pronouna lot of - quantitative adjectiveamazing - pronominal adjectiveelegant - descriptive adjectivewhat kind of - interrogative adjectiveHelens - possessive nounItalian - proper adjectiveboring - pronominal adjectivethree - quantitative adjectivehot - descriptive adjectiveour - possessive adjective