Definition: Mediastinoscopy is a surgery that allows doctors to view the middle of the chest cavity and to do minor surgery through very small incisions. It allows surgeons or pulmonary doctors to remove lymph nodes from between the lungs and to test them for cancer or infection. It is also useful for examining the outside surface of the large tubes of the airways (such as the trachea) or for evaluating tumors or masses in the middle chest. CLICK & SEE THE PICTURES
During a mediastinoscopy, a small incision is made in the neck just above the breastbone or on the left side of the chest next to the breastbone. Then a thin scope (mediastinoscope) is inserted through the opening. A tissue sample (biopsy) can be collected through the mediastinoscope and then examined under a microscope for lung problems, such as infection, inflammation, or cancer. See an illustration of mediastinoscopy.
In many cases mediastinoscopy has been replaced by other biopsy methods that use computed tomography (CT), echocardiography, or bronchoscopy to guide a biopsy needle to the abnormal tissue. Mediastinoscopy may still be needed when these methods cannot be used or when they do not provide conclusive results.
It allows surgeons or pulmonary doctors to remove lymph nodes from between the lungs and to test them for cancer or infection. It is also useful for examining the outside surface of the large tubes of the airways (such as the trachea) or for evaluating tumors or masses in the middle chest.
Why It Is Done? Mediastinoscopy is done to:
* Detect problems of the lungs and mediastinum, such as sarcoidosis.
* Diagnose lung cancer or lymphoma (including Hodgkin’s disease). Mediastinoscopy is often done to check lymph nodes in the mediastinum before considering lung removal surgery to treat lung cancer. Mediastinoscopy can also help your doctor recommend the best treatment (surgery, radiation, chemotherapy) for lung cancer.
* Diagnose certain types of infection, especially those that can affect the lungs (such as tuberculosis).
How To Prepare for the Test?
Discuss to your doctor about any concerns you have regarding the need for the procedure, its risks, how it will be done, or what the results will indicate. This procedure is done by either a surgeon or a trained pulmonary specialist. You will need to sign a consent form giving your surgeon permission to perform this test.
Be sure to discuss with your doctor what may be done following each possible biopsy result. If a lymph node contains cancer, surgery may be done to remove the cancer while you are still asleep. To help you understand the importance of this procedure, fill out the medical test information form (What is a PDF document?) .
Before you have a mediastinoscopy, tell your doctor if you:
* Are taking any medications.
* Have allergies to any medications, including anesthetics.
* Have any bleeding problems or take blood thinners, such as aspirin or warfarin (Coumadin).
* Are or might be pregnant.
Also, certain conditions may make it more difficult to do a mediastinoscopy. Let your doctor know if you have:-
* Had a mediastinoscopy or open-heart surgery in the past. The scarring from the first procedure may make it difficult to do a second procedure.
* A history of neck problems or a neck injury, especially hyperextension of the neck.
* Any physical problems of your chest, including those that have been present since birth (congenital).
* Recently had radiation therapy to the neck or chest.
You will receive general anesthesia and be asleep during the mediastinoscopy. To prepare for your procedure:
* Do not eat or drink anything for at 8 to 10 hours before the procedure. If you take daily medications, ask your doctor whether you should take them on the day of the procedure.
* Leave your jewelry at home. Any jewelry you wear will need to be removed before the procedure.
* Remove glasses, contact lenses, and dentures or a removable bridge just prior to the procedure. These will be given back to you as soon as you wake up after the procedure.
* Arrange to have someone drive you home after the procedure if you do not need to stay in the hospital.
Your doctor may order certain blood tests, such as a complete blood count or bleeding factors, before your procedure.
Before the surgery (sometimes on the same day), you will meet with an anesthesiologist to go over your medical history (including medicines and allergies) and to discuss the anesthesia.
How It Is Done ?
Mediastinoscopy is done in an operating room.Mediastinoscopy is done by a chest (thoracic) surgeon and surgical assistants.
Before the procedure, an intravenous (IV) line will be placed in a vein to give you fluids and medications. After you are asleep, a tube will be placed in your throat (endotracheal or ET tube) to help you breathe during the procedure. Your neck and chest will be washed with an antiseptic soap and covered with a sterile drape.
This procedure is almost always done with general anesthesia, which puts you to sleep so you are unconscious during the procedure. General anesthesia is administered by an anesthesiologist, who asks you to breathe a mixture of gases through a mask. After the anesthetic takes effect, a tube is put down your throat to help you breathe. One reason you need this tube is that your head is tilted far back during the procedure. The tube keeps your throat safely open even while your neck is bending backwards.
An incision will be made just above your breastbone at the base of your neck or on the left side of your chest near the breastbone between the 4th and 5th ribs. A tiny camera on a tube, called a mediastinoscope, is then inserted through the opening. Your doctor can see the work he or she is doing by watching a video screen. Your doctor will examine the space in your chest between your lungs and heart. Lymph nodes or abnormal tissue will be collected for examination. After the scope is removed from your chest, the incision will be closed with a few stitches and covered with a bandage.
The doctor makes one or two other small incisions to allow additional instruments to reach into your chest. These incisions are usually made next to your sternum, between ribs. A wide variety of instruments are useful in mediastinoscopy. These include instruments that can clip away a lymph node and remove it through one of the small chest incisions. Other instruments can be used to stop bleeding blood vessels by using a small electrical current to seal them closed.
At the end of your surgery, the instruments are removed, the lungs are reinflated, and the small incisions are stitched closed. The anesthesia is stopped so that you can wake up within a few minutes of your procedure, although you will remain drowsy for a while afterward.
The entire procedure usually takes about an hour. After the procedure, you will be taken to the recovery room.
Some people may go home after the procedure if the general anesthesia wears off and they are able to swallow fluids without gagging or choking. Other people may need to stay in the hospital for 1 or 2 days. If your stitches are not the dissolving type, you will need to return to your doctor in 10 to 14 days to have them removed. Mediastinoscopy usually leaves only a tiny scar.
How It Feels
Before the procedure you may be given medication that will make you sleepy and relaxed. You will receive general anesthesia during the mediastinoscopy, which will cause you to be asleep. After you wake up, you may feel sleepy for several hours. You may feel tired for 1 to 2 days after the procedure and have some general aches and pains. You may also have a mild sore throat from the tube in your throat during the procedure. Using throat lozenges and gargling with warm salt water may help relieve your sore throat. Risk Factors:
You will have a small straight scar (less than an inch long) wherever the instruments were inserted. You may have some discomfort for a few days in the areas of the incisions. Sometimes work in the middle chest can temporarily injure a nerve, which can weaken your vocal cord muscles for a while and cause hoarseness. In rare cases, bleeding complications might require a transfusion or larger chest surgery. Air leaks from the lung can also occur and occasionally require additional treatment such as a drainage tube, called a chest tube, that is placed into the chest between your ribs and left there for a few days.
General anesthesia is safe for most patients, but it is estimated to result in major or minor complications in 3%-10% of people having surgery of all types. These complications are mostly heart and lung problems and infections.
Complications from mediastinoscopy are uncommon but may include bleeding, infection, a collapsed lung (pneumothorax), a tear in the esophagus, damage to a blood vessel, or injury to a nerve near the voice box (larynx) which may cause permanent hoarseness.
After the procedure, contact your doctor immediately if you have:
* Bleeding from your stitches.
* A fever.
* Severe chest pain.
* Swelling in the neck.
* Shortness of breath.
* Difficulty swallowing.
* Hoarseness of your voice that lasts more than a few days or continues to get worse.
Must you do anything special after the test is over?
You should notify your doctor if you experience fever, shortness of breath, shoulder pain, or chest pain. You should not drive or drink alcohol for the rest of the day.
Mediastinoscopy is a surgical procedure to examine the inside of the chest between and in front of the lungs (mediastinum).
Lymph nodes are small, smooth, and appear normal.
No abnormal tissue, growths, or signs of infection are present.
Lymph nodes may be enlarged or appear abnormal, which may indicate sarcoidosis, infection, or cancer. Tissue samples are removed and examined under the microscope.
Abnormal growths (such as a tumor) or signs of infection (such as an abscess) may be found in the chest cavity, or mediastinum.
What Affects the Test?
If you have had mediastinoscopy or open-heart surgery, you may not be able to have this procedure. Scarring from the first procedure may make it difficult to do a second procedure. What To Think About?
If a lymph node biopsy needs to be examined quickly (while you are still asleep), the sample will be taken immediately to the laboratory. There it will be frozen and sliced into very thin sections for examination under a microscope. If the lymph nodes show that you have cancer, surgery may be done right away to remove the cancer while you are still asleep. If a frozen section sample is not needed, a permanent section is made and the results usually are available in 2 to 4 working days.
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
*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)
*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.
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.
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).
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.
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.
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. 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.
For a long time in the history of science, scientists had relied on tact and finesse in their investigations into Nature. They designed ingenious experiments and constructed exquisite theories to probe into Nature’s patterns. But some of them are now combining finesse with brute force, and in the process uncovering some of Nature’s most profound mysteries.
At the Wellcome Trust Sanger Institute in Cambridge in the United Kingdom, biologists are using brute force like never before in the history of biology. They are sequencing genomes (the full complement of genes in a person) at breakneck speed: about 300 million bases of DNA an hour, seven billion a day, 50 billion a week. In the last six months, scientists there have sequenced more than one trillion letters of genetic code. That is the equivalent of 300 human genomes. Every two minutes, the institute generates as much sequence as was done in the first five years of genome mapping (from 1982-1987).
While sequencing at such a speed, which will itself keep going up each year, biologists are getting closer to answering some critical questions. At a fundamental and philosophical level, it will tell us why we are all so similar and yet so different. At a more practical level, it will tell us why some of us get sick while others don’t. Or to be precise, we will soon know how genetic variation contributes to disease. Says Richard Durbin, co-leader of the three-year 1000 Genome Project that the Institute launched with two other institutions: “At the end of the project, we will have a much clearer picture of what the human genome really looks like.”
The first draft of the human genome, produced by US and UK scientists in 2000, was a major breakthrough in biology. However, there were many gaps in the draft that have still not been plugged. It turns out that the gaps contain the crucial data that we need to understand health and disease. Moreover, the draft was based only on primary data. It is the secondary data, the variations in the reference sequence, which will tell us about risk factors for diseases. That is what biologists are after now.
The power of this technology was unimaginable even two years ago. At that time the institute had 75 machines and could sequence 50 billion bases a year. Now it has 25 machines and can sequence 50 billion bases a week. “We had a major shift in technology last year,” says Harold Swerdlow, head of sequencing technology at the Wellcome Trust Sanger Institute. “The speed of sequencing has gone up 100 times and the cost has gone down by 100 times.”
Without this improvement in technology, the 1000 Genome Project may not have been possible or would have taken too long. As the plans stand now, the first year is for a pilot project. It will do two things: learning to work with the technology, and test the technology itself. Scientists in the project are now sequencing the DNA of 180 people in three equal sets of 60: people of European origin (the sample came from Utah in the US), Africans (sample from Nigeria) and East Asians (sample from China and Japan). The sequencing is at a low depth, a term biologists use to denote the number of times they sequence a gene and thus its accuracy. By the end of the project, they would have sequenced 1000 genomes at an accuracy unavailable so far. They would have had to sequence a genome at least about 40 times to reach this stage.
Maps of genetic variation that exist now are called HapMap. The scientists already have about 130 places of genetic variation that can increase the risk of diabetes, breast cancer, arthritis, inflammatory bowel disease and so on. However, this map identifies variations at a frequency of 5 per cent or more. The 1000 Genome Project will identify gene variations at a frequency of 1 per cent or even less. It will then open up possibilities of developing markers and treatment for a large number of diseases. Says Sameer Brahmachari, a biologist and director general of the Council of Scientific and Industrial Research, New Delhi: “If the physical traits of the sequenced individuals are studied and correlated with their genome, the 1000 genome sequence can be an invaluable resource.”
Taking 10g of cod liver oil a day reduced the need for non-steroidal anti-inflammatory drugs (NSAIDs) by 30%, Dundee University researchers say.
Concerns about side-effects of NSAIDs has prompted research into alternative.
Rheumatologists said the study, in Rheumatology journal, funded by Seven Seas, was small but showed fish oil could benefit some patients.
Patients in the trial were either given cod liver oil or placebo and after 12 weeks asked to gradually reduce their use of NSAIDs, such as ibuprofen.
Almost 60 patients completed the nine-month trial which found 39% taking cod liver oil reduced their daily dose of NSAIDs compared with 10% taking a placebo.
The reduction in drug use was not associated with any worsening of pain or the disease, the researchers reported.
The research team at the University of Dundee have now completed three studies which have all shown patients are able to cut down their NSAID use when taking cold liver oil.
It is thought fatty acids in the fish oil have anti-inflammatory properties.
Some side-effects of NSAIDs, such as an increased risk of stomach bleeding have been known for a long time.
But more recently, concerns have been raised about an apparent increased risk of heart attacks and strokes in those taking the drugs.
Study leader Professor Jill Belch said the study offered hope to many rheumatoid arthritis patients who wanted to reduce the amount of pain medication they take.
“Every change in medication should be discussed with a GP but I would advise people to give cod liver oil a try for 12 weeks alongside their NSAIDs and then try to cut it down if they can manage it but if they don’t manage it, that’s fine.
“If you can get off NSAIDs it will be much safer.”
National Rheumatoid Arthritis Society chief executive Ailsa Bosworth said: “People with rheumatoid arthritis still rely heavily on NSAIDs, even though the safety of these drugs is under scrutiny.
“We look forward to more research in this area.”
British Society for Rheumatology president Dr Andrew Bamji said it was a small study so difficult to draw firm conclusions.
But he added: “Anything that can help to reduce NSAID use is going to be safer for patients.
“It does look as if the results are positive and that is quite interesting.
“I would say to patients by all means take cod liver oil and when you feel ready start to reduce your NSAID dose.”
But he stressed that patients must discuss plans with their doctor because it was important that physicians were aware of all medications and supplements the patient was taking.
“Anything that can help to reduce NSAID use is going to be safer for patients”..says
Dr Andrew Bamji, British Society for Rheumatology
Alzheimer’s disease is a progressive brain disorder that gradually destroys a person’s memory and ability to learn, reason, make judgments, communicate and carry out daily activities. As Alzheimer’s progresses, individuals may also experience changes in personality and behavior, such as anxiety, suspiciousness or agitation, as well as delusions or hallucinations.
“Dementia“ simply means the symptom of a deterioration of intellectual abilities resulting from an unspecified disease or disorder of the brain.Dementia can best be defined as one of the symtoms of Alzheimer’s disease.
Alzheimers Disease is one disease/disorder that causes dementia. Many other illnesses or “syndromes” can also cause dementia. Parkinsons Disease can cause dementia. A stroke can cause dementia. Even dehydration can cause dementia...CLICK & SEE
When people think about staying fit, they generally think from the neck down. But the health of your brain plays a critical role in almost everything you do: thinking, feeling, remembering, working, and playing “ and even sleeping.He can be called a fit person who is perfect in body,mind and sole.
There are two basic types of Alzheimer’s disease: Early-onset Alzheimer’s disease tends to strike people under age 65 and is more likely to run in families. Late-onset Alzheimer’s disease, the much more common type, generally afflicts people after age 65. The exact cause of Alzheimer’s is unknown, although researchers studying this puzzling disease are making progress.
Who Is Affected?
The chances of getting Alzheimer’s disease increase with age. It usually occurs after age 65. Most people are not affected even at advanced ages. Research indicates that there are two definite factors which may increase the risk for Alzheimer’s disease: a family history of dementia and Down’s syndrome.
Family History of Dementia
Some forms of Alzheimer’s disease are inherited. If Alzheimer’s disease has occurred in your family members, other members are more likely to develop it.
Persons with Down’s syndrome have a higher chance of getting Alzheimer’s disease. Close relatives of persons with Down’s syndrome also may be at risk
The good news is that we now know thereâ€™s a lot you can do to help keep your brain healthier as you age. These steps might also reduce your risk of Alzheimerâ€™s disease or other dementia.
Simple lifestyle modifications also would have an enormous impact on our public health and the cost of healthcare woul be reduced. If you make brain-healthy lifestyle changes and take action by getting involved, we could realize a future without Alzheimer’s disease.
1.Try to make you brain healthy and keep you happy in most of your actions.
Like other parts of your body, your brain may lose some agility as you get older. It can deteriorate even more if you donâ€™t take care of it. Science is unlocking many of the mysteries of the brain, but we donâ€™t have all the answers yet.
2.Stay mentally active
This will strengthen your brain cells and improve connections between them.
3. Stay physically active
This will increase the blood flow to the brain as well as encourage new new brain cells.
4. Always try to eat healthy diet.
Research suggests that high cholesterol may contribute to stroke and brain cell damage. A low fat, low cholesterol diet is advisable. And there is growing evidence that a diet rich in dark vegetables and fruits, which contain antioxidants, may help protect brain cells.
I personally believe that regular practice of YOGA and MEDITATION this type of disease can be kept under total control and particularlyPRANAYAM is very good for this.
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.