Differences Between Normal And Alzheimers Brain Biology Essay

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Alzheimer's disease (AD) is a progressive and fatal brain disease. It is a degenerative disorder brain disease. It destroys brain cells, causing memory loss and problems with thinking and behaviour severe enough to affect works, lifelong hobbies or social life. It is also the commonest cause of senile dementia, a general term of memory loss and other intellectual abilities serious enough to interfere with daily life. Patients with Alzheimer's will have two distinct sets of symptoms, which are cognitive and behavioural symptoms. Cognitive symptoms will show that they are losing memory, disorientation and confusion. Memory and abstract reasoning are affected early in the course of the disease, which can eventually render patients unable to care for themselves. They will also suffer from anxiety, hallucinations, depression, insomnia and wandering which these show in behavioural symptoms. Alzheimer's disease was first described in 1906 by a German physician, Alois Alzheimer. The name of this disease was taken from this and it is also known as Senile Dementia of the Alzheimer Type (SDAT). Alzheimer's disease can be treated, but never be cured. So, what are the possible treatments to slow the progression of the disease?

SOLUTION TO PROBLEM

Figure shows the differences between normal and Alzheimer's brain. [(A) 1]

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Cholinesterase inhibitors are a group of drugs prescribed to treat the cognitive symptoms that resulting from Alzheimer's disease. [(A) 2] They aim to increase the level of a brain chemical that synthesized by binding of choline to acetyl A by the enzyme choline acethyltransferase (ChAT) which it is called acetylcholine. [(B) 1] All Alzheimer's have less acetylcholine content in their brain. These inhibitors are also to say to block the activity of enzyme in the brain called cholinesterase from breaking down the neurotransmitter acetylcholine, which is vital for the transmission of nerve impulses. Thus, it can reduce the loss of acetylcholine, which decreasing acetylcholine can cause Alzheimer's disease. There are few drugs have been approved by the U.S. Food and Drug Administration (FDA) for treating cognitive symptoms of Alzheimer's disease. They are galantamine, rivastigmine, donepezil, and tacrine which approved on 2001, 2000, 1996 and 1993 respectively. The drugs work to increase the level of acetylcholine in the brain, but would also induce the side effects. brain AD.png

Figure shows how cholinesterase inhibitors work.For a clearer explanation, it is said that our brain contain neurotransmitter acetylcholine. It is a messenger chemical essential to alertness, judgement, memory and learning. For patients of Alzheimer's, they have less of this neurotransmitter in their brain and also experience over breakdown of acetylcholine. Thus, cause them to have cognitive and behavioural symptoms. So, by taking cholinesterase inhibitors, it will prevent this breakdown. They also may increase acetylcholine levels in the brain and may improve the cellular response to acetylcholine in mild to moderate cases of Alzheimer's. By this maintaining acetylcholine levels, the drugs may help compensate for the loss of functioning brain cells. brain n cholinesterase in brain.jpg

For each of the cholinesterase drugs have different main function and different effectiveness on different individuals. The first cholinesterase inhibitor drug has been approved is tacrine. It has a very short elimination half life. Thus, tacrine is dosed 4 times per daily. This drug has been shown to interact with similarity metabolized drugs such as cimentidine. Tacrine is currently prescribed only rarely for the treatment Alzheimer's disease

While donepezil is considered to offer significant advantages over tacrine, such as lack of associated hepatotoxicity and a longer half life (70 hours), which only need to take once daily dosing. Moreover, greater specificity has been shown by donepezil for brain tissue than tacrine in preclinical trials. One of the advantage of donepezil is it also does not affected by concomitant food intake. The main important role of this drug is as to prevent the breakdown of acetylcholine in the brain.

Figure shows improvement to Alzheimer's patients by taking cholinesterase inhibitors. [(A) 3]Rivastigmine has shown greater selectivity for brain issue in preclinical trials than tacrine and donepezile. It helps in the prevention of the breakdown of acetylcholine and butyrycholine (a chemical brain similar to acetylcholine) in the brain. In fact, in an analysis of rivastigmine use, no pharmacodynamic interactions were detected with 22 concomitantly administered medications. Although concomitant food intake delays absorption of rivastigmine and lowers the maximum plasma concentration, it is still increasing rivastigmine bioavailability by 30%.graph cholinesterase.jpg

Galantamine is a competitive and selective Alzheimer's cholinesterase inhibitors as the function itself to prevent the breaking down of acetylcholine. And it is also more advance drug, which stimulates nicotinic receptors to release more acetylcholine in the brain. It has a half-life of 5 to 6 hours. Simultaneously food intake lowers the rate of absorption of galantamine but does not affect maximum plasma concentration. Each drug differs in how it affects other brain chemicals.

Thus, from the explanation and discussion above, among all of the cholinesterase drugs, galantamine has been found as the most selective and effective drug to reduce negative cognitive and behavioural symptoms in Alzheimer's disease, thus having the greatest clinical efficiency. But, individuals thus respond differently when they take these drugs.

ECONOMIC AND SOCIAL IMPLICATIONS

Even Alzheimer's disease can be treated by taking cholinesterase inhibitors, there are still raise some effects. One of them is the raising of economic implication. As the cholinesterase inhibitors are costly, especially galantamine despite its being more effective and fewer extrapyramidal adverse effects compared to tacrine, donepezil, and rivastigmine. Therefore, this would give a continuous cost to National Health Service (NHS) even there are still others hospitalization of other health care resources need to take important.

Other than that, patients may also get some side effects if there are taking Cholinesterase inhibitors since all drugs still have their disadvantages even can be as a selective treatment. Vomiting, trouble sleeping, uncontrollable movements, loss of appetite and others are the side effects that will be shown on the patients. But, different drugs show differently depends on individuals. This would lead to social impact as these side effects give a burden to the family and people around them.

BENEFITS AND RISKS

Drug treatment medications that have been introduced to treat Alzheimer's disease (cholinesterase inhibitors) are the effective way to use. Even Alzheimer's cannot be cured, but it is proven in clinical trials that people took this medication treatment performed better on memory and thinking tests. It does not totally cured on the patients, but it helps a lot to delay or slow worsening of the symptoms within six months and a year. So, this medication can enhance the quality of life and there will be still a hope.

But it still brings some negative risks and disadvantages since cholinesterase inhibitors impose side effects to the users. They can also cause vomiting and nausea. Other than that, the patients may experience confusion, dizziness and headache which can also lead to schizophrenia. The patients are recommended to take this medication with food to reduce the side effects that may come.

Patients with Alzheimer's usually do not recognise that they are suffered from this disease. Thus, they are late of taking cholinesterase inhibitors medication as their treatment. The patients may face difficulty to adapt the drugs. Patients taking these drugs should be monitored especially when it is just getting started. Doctors usually start them at low drug doses and gradually increase the dosage based on how well a patient tolerate the drugs.

ALTERNATIVE SOLUTIONS

There must be lots of way to overcome specific disease. There is also for Alzheimer's disease. Vitamin E is under continued investigation and seems to be one of the alternative solutions for Alzheimer's showing more promise and it can be rely on. It is effective in enhancing the function of the brain. It is believed that free radicals can damage cell structure and genetic material. The damage can produce oxidative stress and this situation contributes to the development of Alzheimer's disease. This potent antioxidant may help prevent free radical damage the brain. It is described a family of 8 antioxidants which include of 4 tocopherols and 4 tocotrienols. α-tocopherol is the most and the best supplement of vitamin E that is for Alzheimer's. It does not claim to prevent or significantly slow progress of Alzheimer's, but exist of high dose vitamin E may result in some mild functional improvement.

For other remedies to overcome Alzheimer disease, the patient can take Gingko biloba herb. This herb has also been found to be an effective to against Alzheimer's disease. Gingko leaves have two types of chemicals, flavonoids and terpenoids, which both of them have potent antioxidant properties. Referred to the above explanation, antioxidant is substance that will scavenge free radicals. Thus, this Gingko biloba will neutralize free radicals and may also reduce and even help to prevent some of the damage they cause.

Patients of Alzheimer's disease often complain that their taste senses are decreasing. Thus, their appetites should be stimulated to improve the taste sense. Ginger is the best medium and it is categorized in the group of herbs as their role is to improve taste and plus rectifying any digestive problems that might occur. Ginger is Zingiber officinale and it has a pungent taste which is very good for the stimulation of the taste buds. Alternatively, ginger can be eaten in several ways. Ginger snaps could be had with honey. On the other hands, patients can also chop up some pieces of ginger very finely and mix it with little lime juice and pinch of rock salt. Keep chewing on this throughout the day. Make it as a tea is also beneficial. This is one of the effective Alzheimer's cured.

EVALUATION

Alzheimer's disease cannot be cured. But, cholinesterase inhibitors has been found to slow down and delay the worsen symptoms of Alzheimer's disease. [(A) 4] This is from the reference of http://health.msn.com/health-topics/alzheimers-disease/articlepage.aspx?cp-documentid=100230454. We can count on it as it is a reliable since there are some other sources as the back up and are agreeing to it. From the extract taken, "Cholinesterase inhibitors can delay the loss of brain function in people who have mild to moderate Alzheimer's disease.", by German Institute for Quality and Efficiency in Health Care (IQWiG), April 15th 2009 [http://www.informedhealthonline.org/dementia-in-alzheimer-s-disease-how-well-do-cholinesterase-inhibitors.511.en.html]. It also prove and strengthen the above statement, which cholinesterase inhibitors as the main solution for Alzheimer's disease.

BIBLIOGRAPHIES

Web-based Sources (A)

http://www.newswise.com/images/uploads/2009/11/16/HollandBrewerDalePNAS.jpg : retrieved on 23rd November 2009.

http://www.everydayhealth.com/alzheimers/alzheimers-medication.aspx : retrieved on 23rd November 2009.

http://images.google.com.my/imgres?imgurl=http://pipeline.corante.com/NRDD%2520graph.jpg : retrieved on 23rd November 2009.

http://www.informedhealthonline.org/dementia-in-alzheimer-s-disease-how-well-do-cholinesterase-inhibitors.511.en.html: retrieved on 23rd November 2009.

Non Web-based (B)

Per Brodal, 1992, Main Features of Structure and Function, The central Nervous System, New York: Oxford.

Irwin B. Levitan and Loenard K. Kaczmarek, 1991, Cell and Molecular Biology, The Neuron.

Daniel P. Stites and Abba I. Terr, 1991, Neurologic Disease, Basic and Clinical Immunology, California.

Jack R. Cooper, Floyd E. Bloom and Robert Horoth, 1991, The Biochemical Basis of Neuropharmacology.

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