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Aphasia

Description:
Aphasia is the name given to a collection of language disorders caused by damage to the brain.  The word aphasia comes from the wordn aphasia, in Ancient Greek, which means A requirement for a diagnosis of aphasia is that, prior to the illness or injury, the person’s language skills were normal . The difficulties of people with aphasia can range from occasional trouble finding words to losing the ability to speak, read, or write, but does not affect intelligence. This also affects visual language such as sign language. The term “aphasia” implies a problem with one or more functions that are essential and specific to language function. It is not usually used when the language problem is a result of a more peripheral motor or sensory difficulty, such as paralysis affecting the speech muscles or a general hearing impairment.
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Stroke is the most common cause of aphasia in the United States. Approximately 500,000 individuals suffer strokes each year, and 20% of these individuals develop some type of aphasia. Other causes of brain damage include head injuries, brain tumors, and infection. About half of the people who show signs of aphasia have what is called temporary or transient aphasia and recover completely within a few days. An estimated one million Americans suffer from some form of permanent aphasia. As yet, no connection between aphasia and age, gender, or race has been found.
Aphasia is sometimes confused with other conditions that affect speech, such as dysarthria and apraxia. These condition affect the muscles used in speaking rather than language function itself. Dysarthria is a speech disturbance caused by lack of control over the muscles used in speaking, perhaps due to nerve damage. Speech apraxia is a speech disturbance in which language comprehension and muscle control are retained, but the memory of how to use the muscles to form words is not.

Symptoms:
Aphasia is condition characterized by either partial or total loss of the ability to communicate verbally or using written words. A person with aphasia may have difficulty speaking, reading, writing, recognizing the names of objects, or understanding what other people have said. Aphasia is caused by a brain injury, as may occur during a traumatic accident or when the brain is deprived of oxygen during a stroke. It may also be caused by a brain tumor, a disease such as Alzheimer’s, or an infection, like encephalitis. Aphasia may be temporary or permanent. Aphasia does not include speech impediments caused by loss of muscle control.
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To understand and use language effectively, an individual draws upon word memory-stored information on what certain words mean, how to put them together, and how and when to use them properly. For a majority of people, these and other language functions are located in the left side (hemisphere) of the brain. Damage to this side of the brain is most commonly linked to the development of aphasia. Interestingly, however, left-handed people appear to have language areas in both the left and right hemispheres of the brain and, as a result, may develop aphasia from damage to either side of the brain.

People with aphasia may experience any of the following behaviors due to an acquired brain injury, although some of these symptoms may be due to related or concomitant problems such as dysarthria or apraxia and not primarily due to aphasia. Aphasia symptoms can vary based on the location of damage in the brain. Signs and symptoms may or may not be present in individuals with aphasia and may vary in severity and level of disruption to communication. Often those with aphasia will try to hide their inability to name objects by using words like thing. So when asked to name a pencil they may say it is a thing used to write.

*inability to comprehend language
*inability to pronounce, not due to muscle paralysis or weakness
*inability to speak spontaneously
*inability to form words
*inability to name objects (anomia)
*poor enunciation
*excessive creation and use of personal neologisms
*inability to repeat a phrase
*persistent repetition of one syllable, word, or phrase (stereotypies)
*paraphasia (substituting letters, syllables or words)
*agrammatism (inability to speak in a grammatically correct fashion)
*dysprosody (alterations in inflexion, stress, and rhythm)
*incomplete sentences
*inability to read
*inability to write
*limited verbal output
*difficulty in naming
*speech disorder
*Speaking gibberish
*inability to follow or understand simple requests

Causes:
Aphasia is most commonly caused by stroke. It can also be caused by other brain diseases, including cancer (brain tumor), epilepsy, and Alzheimer’s disease, or by a head injury. In rare cases, aphasia may also result from herpesviral encephalitis. The herpes simplex virus affects the frontal and temporal lobes, subcortical structures, and the hippocampal tissue, which can trigger aphasia. In acute disorders, such as head injury or stroke, aphasia usually develops quickly. Aphasia usually develops more slowly from a brain tumor, infection, or dementia.

Although all of the disease listed above are potential causes, aphasia will generally only result when there is substantial damage to the left hemisphere of the brain, either the cortex (outer layer) and/or the underlying white matter. Substantial damage to tissue anywhere within the region shown in blue on the figure below can potentially result in aphasia.  Aphasia can also sometimes be caused by damage to subcortical structures deep within the left hemisphere, including the thalamus, the internal and external capsules, and the caudate nucleus of the basal ganglia.  The area and extent of brain damage or atrophy will determine the type of aphasia and its symptoms.  A very small number of people can experience aphasia after damage to the right hemisphere only. It has been suggested that these individuals may have had an unusual brain organization prior to their illness or injury, with perhaps greater overall reliance on the right hemisphere for language skills than in the general population.

Finally, certain chronic neurological disorders, such as epilepsy or migraine, can also include transient aphasia as a prodromal or episodic symptom.  Aphasia is also listed as a rare side-effect of the fentanyl patch, an opioid used to control chronic pain.

Classification:
Aphasia is best thought of as a collection of different disorders, rather than a single problem. Each individual with aphasia will present with their own particular combination of language strengths and weaknesses. Consequently, it is a major challenge just to document the various difficulties that can occur in different people, let alone decide how they might best be treated. Most classifications of the aphasias tend to divide the various symptoms into broad classes. A common approach is to distinguish between the fluent aphasias (where speech remains fluent, but content may be lacking, and the person may have difficulties understanding others), and the nonfluent aphasias ( where speech is very halting and effortful, and may consist of just one or two words at a time).

However, no such broad-based grouping has proven fully adequate. There is a huge variation among patients within the same broad grouping, and aphasias can be highly selective. For instance, patients with naming deficits (anomic aphasia) might show an inability only for naming buildings, or people, or colors.

Classical-Localizationist approaches:
Localizationist approaches aim to classify the aphasias according to their major presenting characteristics and the regions of the brain that most probably gave rise to them. Inspired by the early work of nineteenth century neurologists Paul Broca and Carl Wernicke, these approaches identify two major subtypes of aphasia and several more minor subtypes:

*Broca’s aphasia (also known as Motor aphasia or Expressive aphasia), which is characterized by halted, fragmented, effortful speech, but relatively well-preserved comprehension. It has been associated with damage to the posterior left prefrontal cortex, most notably Broca’s area. Individuals with Broca’s aphasia often have right-sided weakness or paralysis of the arm and leg, because the left frontal lobe is also important for body movement, particularly on the right side.

*Wernicke’s aphasia (also known as Sensory aphasia or Receptive aphasia), which is characterized by fluent speech, but marked difficulties understanding words and sentences. Although fluent, the speech may lack in key substantive words (nouns, verbs adjectives), and may contain incorrect words or even nonsense words. This subtype has been associated with damage to the posterior left temporal cortex, most notably Wernicke’s area. These individuals usually have no body weakness, because their brain injury is not near the parts of the brain that control movement.

*Other, more minor subtypes include Conduction aphasia, a disorder where speech remains fluent, and comprehension is preserved, but the person may have disproportionate difficulty where repeating words or sentences. Other include Transcortical motor aphasia and Transcortical sensory aphasia which are similar to Broca’s and Wernicke’s aphasia respectively, but the ability to repeat words and sentences is disroportionately preserved.

Recent classification schemes adopting this approach, such as the “Boston-Neoclassical Model”  also group these classical aphasia subtypes into two larger classes: the nonfluent aphasias (which encompasses Broca’s aphasia and transcortical motor aphasia) and the fluent aphasias (which encompasses Wernicke’s aphasia, conduction aphasia and transcortical sensory aphasia). These schemes also identify several further aphasia subtypes, including: Anomic aphasia, which is characterized by a selective difficulty finding the names for things; and Global aphasia where both expression and comprehension of speech are severely compromised.

Many localizationist approaches also recognize the existence of additional, more “pure” forms of language disorder that may affect only a single language skill.  For example, in Pure alexia, a person may be able to write but not read, and in Pure word deafness, they may be able to produce speech and to read, but not understand speech when it is spoken to them.

Cognitive neuropsychological approaches:
Although localizationist approaches provide a useful way of classifying the different patterns of language difficulty into broad groups, one problem is that a sizeable number of individuals do not fit neatly into one category or another. Another problem is that the categories, particularly the major ones such as Broca’s and Wernicke’s aphasia, still remain quite broad. Consequently, even amongst individuals who meet the criteria for classification into a subtype, there can be enormous variability in the types of difficulties they experience.

Instead of categorizing every individual into a specific subtype, cognitive neuropsychological approaches aim to identify the key language skills or “modules” that are not functioning properly in each individual. A person could potentially have difficulty with just one module, or with a number of modules. This type of approach requires a framework or theory as to what skills/modules are needed to perform different kinds of language tasks. For example, the model of Max Coltheart identifies a module that recognizes phonemes as they are spoken, which is essential for any task involving recognition of words. Similarly, there is a module that stores phonemes that the person is planning to produce in speech, and this module is critical for any task involving the production of long words or long strings of speech. One a theoretical framework has been established, the functioning of each module can then be assessed using a specific test or set of tests. In the clinical setting, use of this model usually involves conducting a battery of assessments, each of which tests one or a number of these modules. Once a diagnosis is reached as to the skills/modules where the most significant impairment lies, therapy can proceed to treat these skills.

In practice, the cognitive neuropsychological approach can be unwieldy due to the wide variety of skills that can potentially be tested. Also, it is perhaps best suited to milder cases of aphasia: If the person has little expressive or receptive language ability, sometimes test performance can be difficult to interpret. In practice, clinicians will often use a blend of assessment approaches, which include broad subtyping based on a localizationist framework, and some finer exploration of specific language skills based on the cognitive neuropsychological framework.
Other forms of aphasia:

Progressive aphasias:
Primary progressive aphasia (PPA) is associated with progressive illnesses or dementia, such as frontotemporal dementia / Pick Complex Motor neuron disease, Progressive supranuclear palsy, and Alzheimer’s disease, which is the gradual process of progressively losing the ability to think. It is characterized by the gradual loss of the ability to name objects. People suffering from PPA may have difficulties comprehending what others are saying. They can also have difficulty trying to find the right words to make a sentence. There are three classifications of Primary Progressive Aphasia : Progressive nonfluent aphasia (PNFA), Semantic Dementia (SD), and Logopenic progressive aphasia (LPA)

Progressive Jargon Aphasia is a fluent or receptive aphasia in which the patient’s speech is incomprehensible, but appears to make sense to them. Speech is fluent and effortless with intact syntax and grammar, but the patient has problems with the selection of nouns. Either they will replace the desired word with another that sounds or looks like the original one or has some other connection or they will replace it with sounds. As such, patients with jargon aphasia often use neologisms, and may perseverate if they try to replace the words they cannot find with sounds. Substitutions commonly involve picking another (actual) word starting with the same sound (e.g., clocktower – colander), picking another semantically related to the first (e.g., letter – scroll), or picking one phonetically similar to the intended one (e.g., lane – late).

Deaf aphasia:
There have been many instances showing that there is a form of aphasia among deaf individuals. Sign language is, after all, a form of communication that has been shown to use the same areas of the brain as verbal forms of communication. Mirror neurons become activated when an animal is acting in a particular way or watching another individual act in the same manner. These mirror neurons are important in giving an individual the ability to mimic movements of hands. Broca’s area of speech production has been shown to contain several of these mirror neurons resulting in significant similarities of brain activity between sign language and vocal speech communication. Facial communication is a significant portion of how animals interact with each other. Humans use facial movements to create, what other humans perceive, to be faces of emotions. While combining these facials movements with speech, a more full form of language is created which enables the species to interact with a much more complex and detailed form of communication. Sign language also uses these facial movements and emotions along with the primary hand movement way of communicating. These facial movement forms of communication come from the same areas of the brain. When dealing with damages to certain areas of the brain, vocal forms of communication are in jeopardy of severe forms of aphasia. Since these same areas of the brain are being used for sign language, these same, at least very similar, forms of aphasia can show in the Deaf community. Individuals can show a form of Wernicke’s aphasia with sign language and they show deficits in their abilities in being able to produce any form of expressions. Broca’s aphasia shows up in some patients, as well. These individuals find tremendous difficulty in being able to actually sign the linguistic concepts they are trying to express

Diagnosis:
Following brain injury, an initial bedside assessment is made to determine whether language function has been affected. If the individual experiences difficulty communicating, attempts are made to determine whether this difficulty arises from impaired language comprehension or an impaired ability to speak. A typical examination involves listening to spontaneous speech and evaluating the individual’s ability to recognize and name objects, comprehend what is heard, and repeat sample words and phrases. The individual may also be asked to read text aloud and explain what the passage means. In addition, writing ability is evaluated by having the individual copy text, transcribe dictated text, and write something without prompting.
A speech pathologist or neuropsychologist may be asked to conduct more extensive examinations using in-depth, standardized tests. Commonly used tests include the Boston Diagnostic Aphasia Examination, the Western Aphasia Battery, and possibly, the Porch Index of Speech Ability.

The results of these tests indicate the severity of the aphasia and may also provide information regarding the exact location of the brain damage. This more extensive testing is also designed to provide the information necessary to design an individualized speech therapy program. Further information about the location of the damage is gained through the use of imaging technology, such as magnetic resonance imaging (MRI) and computed tomography scans.
Treatment:
Initially, the underlying cause of aphasia must be treated or stabilized. To regain language function, therapy must begin as soon as possible following the injury. Although there are no medical or surgical procedures currently available to treat this condition, aphasia resulting from stroke or head injury may improve through the use of speech therapy. For most individuals, however, the primary emphasis is placed on making the most of retained language abilities and learning to use other means of communication to compensate for lost language abilities.
Speech therapy is tailored to meet individual needs, but activities and tools that are frequently used include the following:

Exercise and practice. Weakened muscles are exercised by repetitively speaking certain words or making facial expressions, such as smiling.
Picture cards. Pictures of everyday objects are used to improve word recall and increase vocabulary. The names of the objects may also be repetitively spoken aloud as part of an exercise and practice routine.

Picture boards. Pictures of everyday objects and activities are placed together, and the individual points to certain pictures to convey ideas and communicate with others.
Workbooks. Reading and writing exercises are used to sharpen word recall and regain reading and writing abilities. Hearing comprehension is also redeveloped using these exercises.
Computers. Computer software can be used to improve speech, reading, recall, and hearing comprehension by, for example, displaying pictures and having the individual find the right word.

Prognosis:
The degree to which an individual can recover language abilities is highly dependent on how much brain damage occurred and the location and cause of the original brain injury. Other factors include the individual’s age, general health, motivation and willingness to participate in speech therapy, and whether the individual is left or right handed. Language areas may be located in both the left and right hemispheres in left-handed individuals. Left-handed individuals are, therefore, more likely to develop aphasia following brain injury, but because they have two language centers, may recover more fully because language abilities can be recovered from either side of the brain. The intensity of therapy and the time between diagnosis and the start of therapy may also affect the eventual outcome.

Prevention:
Because there is no way of knowing when a stroke, traumatic head injury, or disease will occur, very little can be done to prevent aphasia. However  it can be adviced to be careful in movement of aged person specially for those having high bloodpressure, diabetis and other form of diseases.

Following are some precautions that should be taken to avoid aphasia, by decreasing the risk of stroke, the main cause of aphasia:

*Exercising regularly
*Eating a healthy diet
*Keeping alcohol consumption low and avoiding tobacco use
*Controlling blood pressure

History:
The first recorded case of aphasia is from an Egyptian papyrus, the Edwin Smith Papyrus, which details speech problems in a person with a traumatic brain injury to the temporal lobe.During the second half of the 19th century, Aphasia was a major focus for scientists and philosophers who were working in the beginning stages in the field of psychology.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://en.wikipedia.org/wiki/Aphasia
http://medical-dictionary.thefreedictionary.com/aphasia

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Amyloidosis

Alternative Names: Amyloid – primary

Definition:
In medicine, amyloidosis refers to a variety of conditions in which amyloid proteins are abnormally deposited in organs and/or tissues. A protein is described as being amyloid if, due to an alteration in its secondary structure, it takes on a particular aggregated insoluble form similar to the beta-pleated sheet.  Symptoms vary widely depending upon the site of amyloid deposition. Amyloidosis may be inherited or acquired.

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The collection of these abnormal proteins interferes with the normal functioning of the organ affected.

Since there are more than 20 different proteins that may form amyloid, there are also many different types of amyloidosis.

Classification of amyloid:
The modern classification of amyloid disease tends to use an abbreviation of the protein that makes the majority of deposits, prefixed with the letter A. For example amyloidosis caused by transthyretin is termed “ATTR.” Deposition patterns vary between patients but are almost always composed of just one amyloidogenic protein. Deposition can be systemic (affecting many different organ systems) or organ-specific. Many amyloidoses are inherited, due to mutations in the precursor protein. Other forms are due to different diseases causing overabundant or abnormal protein production – such as with over production of immunoglobulin light chains in multiple myeloma (termed AL amyloid), or with continuous overproduction of acute phase proteins in chronic inflammation (which can lead to AA amyloid).

Out of the approximately 60 amyloid proteins that have been identified so far,  at least 36 have been associated in some way with a human disease.

Amyloidosis is rare, being diagnosed in between one and five in every 100,000 people every year. It’s more common in older people and is also slightly more common in men than in women.

Causes:
The cause of primary amyloidosis is unknown, but the condition is related to abnormal production of antibodies by a type of immune cell called plasma cells.

The symptoms depend on the organs affected by the deposits. These organs can include the tongue, intestines, skeletal and smooth muscles, nerves, skin, ligaments, heart, liver, spleen, and kidneys.

Primary amyloidosis can result in conditions that include:

•Carpal tunnel syndrome
•Gastrointestinal reflux (GERD)
•Heart muscle damage (cardiomyopathy)
•Kidney failure
•Malabsorption
The deposits build up in the affected organs, causing them to become stiff, which decreases their ability to function.

Risk factors have not been identified. Primary amyloidosis is rare. It is similar to multiple myeloma, and is treated the same way.

Symptoms:

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•Enlarged tongue
•Fatigue
•Irregular heart rhythm
•Numbness of hands and feet
•Shortness of breath
•Skin changes
•Swallowing difficulties
•Swelling in the arms and legs
•Weak hand grip
•Weight loss

Additional symptoms that may be associated with this disease:
•Clay-colored stools
•Decreased urine output
•Diarrhea
•Hoarseness or changing voice
•Joint pain
•Other tongue problems
•Weakness

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Diagnosis:
Exams and Tests
Your doctor may discover that you have an enlarged liver or spleen.

If specific organ damage is suspected, your doctor may order tests to confirm amyloidosis of that organ. For example:

•Abdominal ultrasound may reveal a swollen liver or spleen.
•An abdominal fat pad biopsy, rectal mucosa biopsy, or a bone marrow biopsy can help confirm the diagnosis.
•A heart evaluation, including an ECG,may reveal arrhythmias, abnormal heart sounds, or signs of congestive heart failure. An echocardiogram shows poor motion of the heart wall, due to a stiff heart muscle.
•A carpal tunnel syndrome evaluation may show that hand grips are weak.Nerve conduction velocity shows abnormalities.
•Kidney function tests may show signs of kidney failure or too much protein in the urine ( nephrotic syndrome).
?BUN level is increased.
?Serum creatinine is increased.
?Urinalysis shows protein, casts, or fat bodies.

This disease may also alter the results of the following tests:
•Bence-Jones protein (quantitative)
•Carpal tunnel biopsy
•Gum biopsy
•Immunoelectrophoresis – serum
•Myocardial biopsy
•Nerve biopsy
•Quantitative immunoglobulins
•Tongue biopsy
•Urine protein

Treatment:
It isn’t always easy to treat amyloidosis, and there is no treatment yet that specifically targets the amyloid depositing in the tissues. In cases where it’s secondary to another problem (AA amyloidosis), such as rheumatoid arthritis, treating that original problem may stop the progress of amyloidosis or may even reverse it.

In cases of primary amyloidosis (AL amyloidosis), chemotherapy drugs may be given to suppress production of new amyloid and cause regression of existing amyloid deposits.

In secondary amyloidosis, aggressive treatment of the underlying disease can improve symptoms and/or slow progression of disease. Complications such as heart failure, kidney failure, and other problems can sometimes be treated as necessary.

Occasionally, transplantation of a damaged organ is necessary. However, even after this has been carried out the new organ may become affected by amyloidosis.

Treatment may also be aimed at supporting the function of damaged tissues and treating complications such as heart or kidney failure.

Overall, many types of amyloidosis follow a steadily progressive course and may prove fatal within a year or two.

Prognosis :
The severity of the disease depends upon the organs affected. Heart and kidney involvement may lead to organ failure and death. Systemic involvement is associated with death within 1 to 3 years.

Possible Complications:
•Congestive heart failure
•Death
•Endocrine failure (hormonal disorder)
•Kidney failure
•Respiratory failure

Prevention : There is no known prevention.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.bbc.co.uk/health/physical_health/conditions/amyloidosis1.shtml
http://www.nlm.nih.gov/medlineplus/ency/article/000533.htm
http://en.wikipedia.org/wiki/Amyloidosis

http://health.allrefer.com/pictures-images/amyloidosis-on-the-face.html

http://health.allrefer.com/health/cardiac-amyloidosis-dilated-cardiomyopathy.html

http://morningreporttgh.blogspot.com/2010/04/amyloidosis.html

http://gsm.utmck.edu/research/HICP/overview.cfm

http://www.pathologyatlas.ro/amyloidosis-kidney-pathology.php

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Eat Curry With Turmeric to Fight Dementia

This Potent Spice Taken as Little as Once a Week Can Fight Dementia

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New research shows that eating curry once or twice a week could help prevent the onset of Alzheimer’s disease and dementia. The key reason is curcumin, a component of the spice turmeric.

Curcumin prevents the spread of amyloid protein plaques, which are thought to cause dementia. Amyloid plaques, along with tangles of nerve fibers, contribute to the degradation of the wiring in brain cells.

There is evidence that people who eat a curry meal two or three times a week have a lower risk of dementia. Researchers are currently testing the impact of higher doses, such as the equivalent of going on a curry spree for a week, to see if they can maximize the effect.

You may click to see:->Turmeric May Work for Alzheimer’s

Resources:
BBC News June 3, 2009
Royal College of Psychiatrists’ Annual Meeting, Liverpool, UK, June 2-5, 2009

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Turmeric Curry Keeps Dementia at Bay

Turmeric curry once or twice a week could keep Alzheimer’s disease and dementia at bay, thanks to a magic ingredient curcumin found  in the spice, according to an Indian American psychiatrist.
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Murali Doraiswamy, psychiatry professor at the Mental Fitness Lab of the Duke University Medical Centre (DUMC), North Carolina, told delegates at the Royal College of Psychiatrists‘ annual meeting Liverpool that curcumin prevented the spread of amyloid plaques. These plaques are thought to contribute to the degradation of the wiring in brain cells and lead to the subsequent symptoms of Alzheimer’s disease
.

Doraiswamy, who did his MBBS from Madras University (India) in 1987, said: “There is very solid evidence that curcumin binds to plaques, and basic research on animals engineered to produce human amyloid plaques has shown benefits.

“Turmeric has been studied not just in Alzheimer’s research but for a variety of conditions, such as cancer and arthritis. Turmeric is often referred to as the spice of life in ancient Indian medical lore,” said Doraiswamy.

A clinical trial is now underway at the University of California, Los Angeles, to test curcumin’s effects in Alzheimer’s patients and specifically on their amyloid plaque proteins. A small pilot trail was completed to determine the right dose and researchers have now embarked on a larger study.

Doraiswamy told the Royal College annual meeting that “you can modify a mouse so that at about 12 months its brain is riddled with plaques. If you feed this rat a curcumin-rich diet it dissolves these plaques”.

However, curry may be just one of the ingredients that prevent degeneration of the brain. “If you are eating fatty burgers and smoking then don’t expect an occasional curry to counterbalance a poor lifestyle,” he said.

Turmeric is also found in mustard and Doraiswamy predicted a day when – for those unable, or unwilling, to consume curries regularly – the public might be advised to take a ‘curry’ pill every day if the findings are confirmed in human studies, said a DUMC release.

Doraiswamy, a leading expert on brain health and fitness, is on a lecture tour promoting his book, “The Alzheimer’s Action Plan”, published in April.

Source:
The Times Of India

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Down Syndrome

Boy assembling a book case

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Definition
Down syndrome is the most common cause of mental retardation and malformation in a newborn. It occurs because of the presence of an extra chromosome.

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Chromosomes are the units of genetic information that exist within every cell of the body. Twenty-three distinctive pairs, or 46 total chromosomes, are located within the nucleus (central structure) of each cell. When a baby is conceived by the combining of one sperm cell with one egg cell, the baby receives 23 chromosomes from each parent, for a total of 46 chromosomes. Sometimes, an accident in the production of a sperm or egg cell causes that cell to contain 24 chromosomes. This event is referred to as nondisjunction. When this defective cell is involved in the conception of a baby, that baby will have a total of 47 chromosomes. The extra chromosome in Down syndrome is labeled number 21. For this reason, the existence of three such chromosomes is sometimes referred to as Trisomy 21.

In a very rare number of Down syndrome cases (about 1–2%), the original egg and sperm cells are completely normal. The problem occurs sometime shortly after fertilization; during the phase where cells are dividing rapidly. One cell divides abnormally, creating a line of cells with an extra chromosome 21. This form of genetic disorder is called a mosaic. The individual with this type of Down syndrome has two types of cells: those with 46 chromosomes (the normal number), and those with 47 chromosomes (as occurs in Down syndrome). Some researchers have suggested that individuals with this type of mosaic form of Down syndrome have less severe signs and symptoms of the disorder.

Another relatively rare genetic accident which can cause Down syndrome is called translocation. During cell division, the number 21 chromosome somehow breaks. A piece of the 21 chromosome then becomes attached to another chromosome. Each cell still has 46 chromosomes, but the extra piece of chromosome 21 results in the signs and symptoms of Down syndrome. Translocations occur in about 3–4% of cases of Down syndrome.

Down syndrome occurs in about one in every 800–1,000 births. It affects an equal number of boys and girls. Less than 25% of Down syndrome cases occur due to an extra chromosome in the sperm cell. The majority of cases of Down syndrome occur due to an extra chromosome 21 within the egg cell supplied by the mother (nondisjunction). As a woman’s age (maternal age) increases, the risk of having a Down syndrome baby increases significantly. For example, at younger ages, the risk is about one in 4,000. By the time the woman is age 35, the risk increases to one in 400; by age 40 the risk increases to one in 110; and by age 45 the risk becomes one in 35. There is no increased risk of either mosaicism or translocation with increased maternal age.

Causes and Symptoms:-
While Down syndrome is a chromosomal disorder, a baby is usually identified at birth through observation of a set of common physical characteristics. Babies with Down syndrome tend to be overly quiet, less responsive, with weak, floppy muscles. Furthermore, a number of physical signs may be present. These include:

*flat appearing face
*small head
*flat bridge of the nose
*smaller than normal, low-set nose
*small mouth, which causes the tongue to stick out and to appear overly large
*upward slanting eyes
*extra folds of skin located at the inside corner of each eye, near the nose (called epicanthal folds)
*rounded cheeks
*small, misshapen ears
*small, wide hands
*an unusual, deep crease across the center of the palm (called a simian crease)
*a malformed fifth finger
*a wide space between the big and the second toes
*unusual creases on the soles of the feet
*overly-flexible joints (sometimes referred to as being double-jointed)
*ahorter than normal height

Other types of defects often accompany Down syndrome. About 30–50% of all children with Down syndrome are found to have heart defects. A number of different heart defects are common in Down syndrome, including abnormal openings (holes) in the walls that separate the heart’s chambers (atrial septal defect, ventricular septal defect). These result in abnormal patterns of blood flow within the heart. The abnormal blood flow often means that less oxygen is sent into circulation throughout the body. Another heart defect that occurs in Down syndrome is called Tetralogy of Fallot. Tetralogy of Fallot consists of a hole in the heart, along with three other major heart defects.

Malformations of the gastrointestinal tract are present in about 5–7% of children with Down syndrome. The most common malformation is a narrowed, obstructed duodenum (the part of the intestine into which the stomach empties). This disorder, called duodenal atresia, interferes with the baby’s milk or formula leaving the stomach and entering the intestine for digestion. The baby often vomits forcibly after feeding, and cannot gain weight appropriately until the defect is repaired.

Other medical conditions that occur in patients with Down syndrome include an increased chance of developing infections, especially ear infections and pneumonia; certain kidney disorders; thyroid disease (especially low or hypothyroid); hearing loss; vision impairment requiring glasses (corrective lenses); and a 20-times greater chance of developing leukemia (a blood disorder).

Development in a baby and child with Down syndrome occurs at a much slower than normal rate. Because of weak, floppy muscles (hypotonia), babies learn to sit up, crawl, and walk much later than their normal peers. Talking is also quite delayed. The level of mental retardation is considered to be mild-to-moderate in Down syndrome. The actual IQ range of Down syndrome children is quite varied, but the majority of such children are in what is sometimes known as the trainable range. This means that most people with Down syndrome can be trained to do regular self-care tasks, function in a socially appropriate manner in a normal home environment, and even hold simple jobs.

As people with Down syndrome age, they face an increased chance of developing the brain disease called Alzheimer’s (sometimes referred to as dementia or senility). Most people have a six in 100 risk of developing Alzheimer’s, but people with Down syndrome have a 25 in 100 chance of the disease. Alzheimer’s disease causes the brain to shrink and to break down. The number of brain cells decreases, and abnormal deposits and structural arrangements occur. This process results in a loss of brain functioning. People with Alzheimer’s have strikingly faulty memories. Over time, people with Alzheimer’s disease will lapse into an increasingly unresponsive state. Some researchers have shown that even Down syndrome patients who do not appear to have Alzheimer’s disease have the same changes occurring to the structures and cells of their brains.

As people with Down syndrome age, they also have an increased chance of developing a number of other illnesses, including cataracts, thyroid problems, diabetes, and seizure disorders.

Diagnosises:-
Diagnosis is usually suspected at birth, when the characteristic physical signs of Down syndrome are noted. Once this suspicion has been raised, genetic testing (chromosome analysis) can be undertaken in order to verify the presence of the disorder. This testing is usually done on a blood sample, although chromosome analysis can also be done on other types of tissue, including skin. The cells to be studied are prepared in a laboratory. Chemical stain is added to make the characteristics of the cells and the chromosomes stand out. Chemicals are added to prompt the cells to go through normal development, up to the point where the chromosomes are most visible, prior to cell division. At this point, they are examined under a microscope and photographed. The photograph is used to sort the different sizes and shapes of chromosomes into pairs. In most cases of Down syndrome, one extra chromosome 21 will be revealed. The final result of such testing, with the photographed chromosomes paired and organized by shape and size, is called the individual’s karyotype.

Two types of prenatal tests are used to detect Down syndrome in a fetus: screening tests and diagnostic tests. Screening tests estimate the risk that a fetus has DS; diagnostic tests can tell whether the fetus actually has the condition.

Screening tests are cost-effective and easy to perform. But because they can’t give a definitive answer as to whether a baby has DS, these tests are used to help parents decide whether to have more diagnostic tests.

Diagnostic tests are about 99% accurate in detecting Down syndrome and other chromosomal abnormalities. However, because they’re performed inside the uterus, they are associated with a risk of miscarriage and other complications.

For this reason, invasive diagnostic testing previously was generally recommended only for women age 35 or older, those with a family history of genetic defects, or those who’ve had an abnormal result on a screening test.

However, the American College of Obstetrics and Gynecology (ACOG) now recommends that all pregnant women be offered screening with the option for invasive diagnostic testing for Down syndrome, regardless of age.

If you’re unsure about which test, if any, is right for you, your doctor or a genetic counselor can help you sort through the pros and cons of each.

Screening tests include:-
*Nuchal translucency testing. This test, performed between 11 and 14 weeks of pregnancy, uses ultrasound to measure the clear space in the folds of tissue behind a developing baby’s neck. (Babies with DS and other chromosomal abnormalities tend to accumulate fluid there, making the space appear larger.) This measurement, taken together with the mother’s age and the baby’s gestational age, can be used to calculate the odds that the baby has DS. Nuchal translucency testing is usually performed along with a maternal blood test.

*The triple screen or quadruple screen (also called the multiple marker test). These tests measure the quantities of normal substances in the mother’s blood. As the names imply, triple screen tests for three markers and quadruple screen includes one additional marker and is more accurate. These tests are typically offered between 15 and 18 weeks of pregnancy.

*Integrated screen. This uses results from first trimester screening tests (with or without nuchal translucency) and blood tests with second trimester quad screen to come up with the most accurate screening results.

*A genetic ultrasound. A detailed ultrasound is often performed at 18 to 20 weeks in conjunction with the blood tests, and it checks the fetus for some of the physical traits abnormalities associated with Down syndrome.

Diagnostic tests include:-
*Chorionic villus sampling (CVS). CVS involves taking a tiny sample of the placenta, either through the cervix or through a needle inserted in the abdomen. The advantage of this test is that it can be performed during the first trimester, between 8 and 12 weeks. The disadvantage is that it carries a slightly greater risk of miscarriage as compared with amniocentesis and has other complications.

*Amniocentesis. This test, performed between 15 and 20 weeks of pregnancy, involves the removal of a small amount of amniotic fluid through a needle inserted in the abdomen. The cells can then be analyzed for the presence of chromosomal abnormalities. Amniocentesis carries a small risk of complications, such as preterm labor and miscarriage.

*Percutaneous umbilical blood sampling (PUBS). Usually performed after 20 weeks, this test uses a needle to retrieve a small sample of blood from the umbilical cord. It carries risks similar to those associated with amniocentesis.
After a baby is born, if the doctor suspects DS based on the infant’s physical characteristics, a karyotype — a blood or tissue sample stained to show chromosomes grouped by size, number, and shape — can be performed to verify the diagnosis.

Treatment:-
No treatment is available to cure Down syndrome. Treatment is directed at addressing the individual concerns of a particular patient. For example, heart defects will many times require surgical repair, as will duodenal atresia. Many Down syndrome patients will need to wear glasses to correct vision. Patients with hearing impairment benefit from hearing aids.

At one time, most children with Down syndrome did not live past childhood. Many would often become sick from infections. Others would die from their heart problems or other problems they had at birth. Today, most of these health problems can be treated and most children who have it will grow into adulthood.

Medicines can help with infections and surgery can correct heart, stomach, and intestinal problems. If the person gets leukaemia, there are medical treatments that can be very successful. Someone with Down syndrome has a good chance of living to be 50 years old or more.

A new drug, referred to as a “smart drug,” has been receiving some attention in the treatment of Down syndrome patients. This drug, piracetam, has not been proven to increase intellectual ability, despite testimonials that have been receiving attention on television and the Internet. Piracetam has not been approved for use in the United States, although it is being sold via the Internet. The National Down Syndrome Society and the National Down Syndrome Congress do not recommend the use of this drug as of 2001.

While some decades ago, all Down syndrome children were quickly placed into institutions for lifelong care. Research shows very clearly that the best outlook for children with Down syndrome is a normal family life in their own home. This requires careful support and education of the parents and the siblings. It is a life-changing event to learn that a new baby has a permanent condition that will effect essentially all aspects of his or her development. Some community groups exist to help families deal with the emotional effects of this new information, and to help plan for the baby’s future. Schools are required to provide services for children with Down syndrome, sometimes in separate special education classrooms, and sometimes in regular classrooms (this is called mainstreaming or inclusion).

Prognosis:-
The prognosis in Down syndrome is quite variable, depending on the types of complications (heart defects, susceptibility to infections, development of leukemia) of each individual baby. The severity of the retardation can also vary significantly. Without the presence of heart defects, about 90% of children with Down syndrome live into their teens. People with Down syndrome appear to go through the normal physical changes of aging more rapidly, however. The average age of death for an individual with Down syndrome is about 50–55 years.

Still, the prognosis for a baby born with Down syndrome is better than ever before. Because of modern medical treatments, including antibiotics to treat infections and surgery to treat heart defects and duodenal atresia, life expectancy has greatly increased. Community and family support allows people with Down syndrome to have rich, meaningful relationships. Because of educational programs, some people with Down syndrome are able to hold jobs.

Men with Down syndrome appear to be uniformly sterile (meaning that they are unable to have offspring). Women with Down syndrome, however, are fully capable of having babies. About 50% of these babies, however, will also be born with Down syndrome.

Prevention:-
Efforts at prevention of Down syndrome are aimed at genetic counseling of couples who are preparing to have babies. A counselor needs to inform a woman that her risk of having a baby with Down syndrome increases with her increasing age. Two types of testing is available during a pregnancy to determine if the baby being carried has Down syndrome.

Screening tests are used to estimate the chance that an individual woman will have a baby with Down syndrome. At 14–17 weeks of pregnancy, measurements of a substance called AFP (alpha-fetoprotein) can be performed. AFP is normally found circulating in the blood of a pregnant woman, but may be unusually high or low with certain disorders. Carrying a baby with Down syndrome often causes AFP to be lower than normal. This information alone, or along with measurements of two other hormones, is considered along with the mother’s age to calculate the risk of the baby being born with Down syndrome. These results are only predictions, and are only correct about 60% of the time.

The only way to definitively establish (with about 98–99% accuracy) the presence or absence of Down syndrome in a developing baby, is to test tissue from the pregnancy itself. This is usually done either by amniocentesis or chorionic villus sampling (CVS). In amniocentesis, a small amount of the fluid in which the baby is floating is withdrawn with a long, thin needle. In chorionic villus sampling, a tiny tube is inserted into the opening of the uterus to retrieve a small sample of the placenta (the organ that attaches the growing baby to the mother via the umbilical cord, and provides oxygen and nutrition). Both amniocentesis and CVS allow the baby’s own karyotype to be determined. A couple must then decide whether to use this information in order to begin to prepare for the arrival of a baby with Down syndrome, or to terminate the pregnancy.

Once a couple has had one baby with Down syndrome, they are often concerned about the likelihood of future offspring also being born with the disorder. Most research indicates that this chance remains the same as for any woman at a similar age. However, when the baby with Down syndrome has the type that results from a translocation, it is possible that one of the two parents is a carrier of that defect. A carrier “carries” the genetic defect, but does not actually have the disorder. When one parent is a carrier of a translocation, the chance of future offspring having Down syndrome is greatly increased. The specific risk will have to be calculated by a genetic counselor.

Research:-
Main article: Research of Down syndrome-related genes
Down syndrome is “a developmental abnormality characterized by trisomy of human chromosome 21″ (Nelson 619). The extra copy of chromosome-21 leads to an over expression of certain genes located on chromosome-21.

Research by Arron et al shows that some of the phenotypes associated with Down Syndrome can be related to the dysregulation of transcription factors (596), and in particular, NFAT. NFAT is controlled in part by two proteins, DSCR1 and DYRK1A; these genes are located on chromosome-21 (Epstein 582). In people with Down Syndrome, these proteins have 1.5 times greater concentration than normal (Arron et al. 597). The elevated levels of DSCR1 and DYRK1A keep NFAT primarily located in the cytoplasm rather than in the nucleus, preventing NFATc from activating the transcription of target genes and thus the production of certain proteins (Epstein 583).

This dysregulation was discovered by testing in transgenic mice that had segments of their chromosomes duplicated to simulate a human chromosome-21 trisomy (Arron et al. 597). A test involving grip strength showed that the genetically modified mice had a significantly weaker grip, much like the characteristically poor muscle tone of an individual with Down Syndrome (Arron et al. 596). The mice squeezed a probe with a paw and displayed a .2 newton weaker grip (Arron et al. 596). Down syndrome is also characterized by increased socialization. When modified and unmodified mice were observed for social interaction, the modified mice showed as much as 25% more interactions as compared to the unmodified mice (Arron et al. 596).

The genes that may be responsible for the phenotypes associated may be located proximal to 21q22.3. Testing by Olson et al. in transgenic mice show the duplicated genes presumed to cause the phenotypes are not enough to cause the exact features. While the mice had sections of multiple genes duplicated to approximate a human chromosome-21 triplication, they only showed slight craniofacial abnormalities (688-690). The transgenic mice were compared to mice that had no gene duplication by measuring distances on various points on their skeletal structure and comparing them to the normal mice (Olson et al. 687). The exact characteristics of Down Syndrome were not observed, so more genes involved for Down Syndrome phenotypes have to be located elsewhere.

Reeves et al, using 250 clones of chromosome-21 and specific gene markers, were able to map the gene in mutated bacteria. The testing had 99.7% coverage of the gene with 99.9995% accuracy due to multiple redundancies in the mapping techniques. In the study 225 genes were identified (311-313).

The search for major genes that may be involved in Down syndrome symptoms is normally in the region 21q21–21q22.3. However, studies by Reeves et al. show that 41% of the genes on chromosome-21 have no functional purpose, and only 54% of functional genes have a known protein sequence. Functionality of genes was determined by a computer using exon prediction analysis (312). Exon sequence was obtained by the same procedures of the chromosome-21 mapping.

Research has led to an understanding that two genes located on chromosome-21, that code for proteins that control gene regulators, DSCR1 and DYRK1A can be responsible for some of the phenotypes associated with Down Syndrome. DSCR1 and DYRK1A cannot be blamed outright for the symptoms; there are a lot of genes that have no known purpose. Much more research would be needed to produce any appropriate or ethically acceptable treatment options.

Recent use of transgenic mice to study specific genes in the Down syndrome critical region has yielded some results. APP is an Amyloid beta A4 precursor protein. It is suspected to have a major role in cognitive difficulties. Another gene, ETS2 is Avian Erythroblastosis Virus E26 Oncogene Homolog 2. Researchers have “demonstrated that over-expression of ETS2 results in apoptosis. Transgenic mice over-expressing ETS2 developed a smaller thymus and lymphocyte abnormalities, similar to features observed in Down syndrome.”

Vitamin supplements, in particular supplemental antioxidants and folinic acid, have been shown to be ineffective in the treatment of Down syndrome.

Sociological and cultural aspects:-
Advocates for people with Down syndrome point to various factors, such as additional educational support and parental support groups to improve parenting knowledge and skills. There are also strides being made in education, housing, and social settings to create environments which are accessible and supportive to people with Down syndrome. In most developed countries, since the early twentieth century many people with Down syndrome were housed in institutions or colonies and excluded from society. However, since the early 1960s parents and their organizations (such as MENCAP), educators and other professionals have generally advocated a policy of inclusion, bringing people with any form of mental or physical disability into general society as much as possible. In many countries, people with Down syndrome are educated in the normal school system; there are increasingly higher-quality opportunities to move from special (segregated) education to regular education settings.

Despite these changes, the additional support needs of people with Down syndrome can still pose a challenge to parents and families. Although living with family is preferable to institutionalization, people with Down syndrome often encounter patronizing attitudes and discrimination in the wider community.

The first World Down Syndrome Day was held on 21 March 2006. The day and month were chosen to correspond with 21 and trisomy respectively. It was proclaimed by European Down Syndrome Association during their European congress in Palma de Mallorca (febr. 2005). In the United States, the National Down Syndrome Society observes Down Syndrome Month every October as “a forum for dispelling stereotypes, providing accurate information, and raising awareness of the potential of individuals with Down syndrome.” In South Africa, Down Syndrome Awareness Day is held every October 20.[49] Organizations such as Special Olympics Hawaii provide year-round sports training for individuals with intellectual disabilities such as down syndrome.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.answers.com/topic/down-syndrome-diagnosis
http://kidshealth.org/parent/medical/genetic/down_syndrome.html
http://www.charliebrewersworld.com/page4.htm
http://en.wikipedia.org/wiki/Down_syndrome

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