Sunday, August 3, 2008
What is Multiple Intelligence?
Conceived by Howard Gardner, Multiple Intelligences are seven different ways to demonstrate intellectual ability.
What are the types of Multiple Intelligence?
ability to perceive the visual. These learners tend to think in pictures and need to create vivid mental images to retain information. They enjoy looking at maps, charts, pictures, videos, and movies.
Their skills include:
puzzle building, reading, writing, understanding charts and graphs, a good sense of direction, sketching, painting, creating visual metaphors and analogies (perhaps through the visual arts), manipulating images, constructing, fixing, designing practical objects, interpreting visual images.
Possible career interests:
navigators, sculptors, visual artists, inventors, architects, interior designers, mechanics, engineers
ability to use words and language. These learners have highly developed auditory skills and are generally elegant speakers. They think in words rather than pictures.
Their skills include:
listening, speaking, writing, story telling, explaining, teaching, using humor, understanding the syntax and meaning of words, remembering information, convincing someone of their point of view, analyzing language usage.
Possible career interests:
Poet, journalist, writer, teacher, lawyer, politician, translator
ability to use reason, logic and numbers. These learners think conceptually in logical and numerical patterns making connections between pieces of information. Always curious about the world around them, these learner ask lots of questions and like to do experiments.
Their skills include:
problem solving, classifying and categorizing information, working with abstract concepts to figure out the relationship of each to the other, handling long chains of reason to make local progressions, doing controlled experiments, questioning and wondering about natural events, performing complex mathematical calculations, working with geometric shapes
Possible career paths:
Scientists, engineers, computer programmers, researchers, accountants, mathematicians
ability to control body movements and handle objects skillfully. These learners express themselves through movement. They have a good sense of balance and eye-hand co-ordination. (e.g. ball play, balancing beams). Through interacting with the space around them, they are able to remember and process information.
Their skills include:
dancing, physical co-ordination, sports, hands on experimentation, using body language, crafts, acting, miming, using their hands to create or build, expressing emotions through the body
Possible career paths:
Athletes, physical education teachers, dancers, actors, firefighters, artisans
ability to produce and appreciate music. These musically inclined learners think in sounds, rhythms and patterns. They immediately respond to music either appreciating or criticizing what they hear. Many of these learners are extremely sensitive to environmental sounds (e.g. crickets, bells, dripping taps).
Their skills include:
singing, whistling, playing musical instruments, recognizing tonal patterns, composing music, remembering melodies, understanding the structure and rhythm of music
Possible career paths:
musician, disc jockey, singer, composer
ability to relate and understand others. These learners try to see things from other people's point of view in order to understand how they think and feel. They often have an uncanny ability to sense feelings, intentions and motivations. They are great organizers, although they sometimes resort to manipulation. Generally they try to maintain peace in group settings and encourage co-operation.They use both verbal (e.g. speaking) and non-verbal language (e.g. eye contact, body language) to open communication channels with others.
Their skills include:
seeing things from other perspectives (dual-perspective), listening, using empathy, understanding other people's moods and feelings, counseling, co-operating with groups, noticing people's moods, motivations and intentions, communicating both verbally and non-verbally, building trust, peaceful conflict resolution, establishing positive relations with other people.
Possible Career Paths:
Counselor, salesperson, politician, business person
ability to self-reflect and be aware of one's inner state of being. These learners try to understand their inner feelings, dreams, relationships with others, and strengths and weaknesses.
Their Skills include:
Recognizing their own strengths and weaknesses, reflecting and analyzing themselves, awareness of their inner feelings, desires and dreams, evaluating their thinking patterns, reasoning with themselves, understanding their role in relationship to others
Possible Career Paths:
Researchers, theorists, philosophers
Posted byDoc Junhel at 11:10 PM
20th (early decades of the century), behaviorism gained popularity as a guiding psychological theory. Behaviorism reigned as the dominant model in psychology, largely due to the creation of conditioning theories as scientific models of human behavior, and their successful application in the workplace and in fields such as advertising and military science.
Qualitative psychological research and Quantitative psychological research.
Abnormal psychology is the study of abnormal behavior in order to describe, predict, explain, and change abnormal patterns of functioning.
The nature of thought is another core interest in psychology. Cognitive psychology studies cognition, the mental processes underlying behavior.
Comparative psychology refers to the study of the behavior and mental life of animals other than human beings. It is related to disciplines outside of psychology that study animal behavior, such as ethology.
Social psychology is the study of the nature and causes of human social behavior, with an emphasis on how people think towards each other and how they relate to each other.
Quantitative psychology involves the application of mathematical and statistical modeling in psychological research, and the development of statistical methods for analyzing and explaining behavioral data.
Psychometrics is the field of psychology concerned with the theory and technique of psychological measurement, which includes the measurement of knowledge, abilities, attitudes, and personality traits
Posted byDoc Junhel at 7:03 PM
¡ Sociology (from Latin socious”companion and suffix –logy “the study of from Greek logos “knowledge )is scientific or systematic study of society including patterns of social relationships, interaction and culture. Areas studied in sociology can range from analysis of brief contact s between anonymous individuals on the street to the study of global social interaction, numerous fields within the discipline concentrated on how and why people are organized in society either as individuals or as members of associations, groups and institutions.
¡ Sociological Theories
¡ Sociological theories are complex theoretical frameworks that sociologist use to explain and analyze variously how social action. Social processes and social structures work. Sociological theories are sometimes called social theories though the later term generally refers to interdisciplinary theory .In seeking to understand society, sociologist use both sociological theory and interdisciplinary social theories to organize social research.
¡ . Structural Functionalism
¡ Structural functionalist believe that society leans toward equilibrium and social order. They see society like a human body, in which institutions such as education are like important organs that keep the society /body healthy and well. Social health means the same social order and is guaranteed when nearly everyone accepts the general moral values of their society. Hence structural functionalist believe the aim of key institutions, such as education is to socialize children and teenagers. Socialisation is the process by which the new generation learns the knowledge, attitudes and values that they will need as productive citizens. Although this aim is stated in formal curriculum it is mainly achieved through he hidden curriculum, a subtler, but nonetheless powerful, indocrination of the norms and values of the wider society. Students learn these values because their behavior at school is regulated until they gradually internalize and accept them. Education must however perform another function .as various jobs become vacant. They must be filled with the appropriate people. Therefore the other purpose of education is to sort and ranks individuals for placement in the labor market. Those with high achievement will be trained for the most important jobs and in reward, be given the highest incomes. Those who achieved the least, will be given the least demanding jobs, and hence the least income.
¡ According to Sennet and Cobb however,”to believe that ability alone decides who is rewarded is to be deceived “megham agrees sating that large numbers of capable students from the working class backgrounds fail to achieve satisfactory standards in school and therefore e fail to obtain the status they deserve, Jacob believes this is because the middle class cultural experiences that are provided at school may be contrary to the experiences working-class children receive at home .In other words, working class children are not adequately prepared to cope at school. They are therefore “cooled out” from school with the least qualifications, hence they get the least desirable jobs and so remain working class. Argent confirms this cycle, arguing that schooling supports continuity, which in turn support social order. Talcott Parsons believe d that this process, whereby some students were identified and labeled educational failures “was a necessary activity which one part of the social system ,education ,performed for the whole yet the structural functionalist perspective maintains that this social order ,this continuity is what most people desire. The weakness of this perspective thus becomes evident .Why would the working class wish to stay working class? Such an inconsistency demonstrates that another perspective may be useful.
¡ Conflict Theory
¡ The conflict theory contrary to their her structural functionalist perspective. Believes that society is full of vying social groups with different aspirations, different access to life chances and gains different social rewards. Relation in society, in this view is mainly based on exploitation, oppression, domination and subordination. This is a more cynical picture of society than the previous idea that most people accept continuing inequality. Some conflict theorist believe education is controlled by the state which is controlled by the powerful and its purpose is to reproduce existing inequalities, as well as legitimize “acceptable ideas which actually work to reinforce the privileged position of the dominant group. Education achieves its purpose by maintaining the status quo.where lower-class children becomes lower class adults and middle class children become middle and upper –class adults. This cycle occurs because the dominant group has, overtime closely aligned education with middle class values and aims, thus alienating people of the other classes. Many teachers assume that students will have particular middle class experiences at home, and for some children this assumption isn’t necessarily true. Some children are expected to help their parents after school and carry considerable domestic responsibilities in their often –single parent home. The demands of this domestic labor often make it difficult for them to find time to do all their homework and thus affect their academic performance.
¡ Ethno methodology:
¡ Examines how people make sense out of social life in the process of living it as if each was as researcher engaged in enquiry.
¡ Feminist theory
¡ Focuses on how male dominance of society has shaped social life.
¡ Interpretative sociology
¡ This theoretical perspective, based in the work of Max Weber, proposes social, economic and historical research can never be fully empirical or descriptive, as one must always approach it wit conceptual apparatus.
¡ Social phenomenology
¡ The social phenomenology of Alfred Schultz influenced the development of the social constructivism and ethnomethology.
¡ Social positivism
¡ Social positivist believes that social process es should be studied in terms of cause and effect using scientific method.
¡ Symbolic interactionism
¡ Examines how shared meanings and social patterns are developed in the course of social interactions.
¡ Dramaturgical perspective
¡ A specialized symbolic interactionism paradigm developed by Irving Goff man seeing life as a performance
¡ Rational choice theory –Models social behavior as the interaction of utility maximizing individuals..
Posted byDoc Junhel at 6:57 PM
Expressive Language Disorder
a communication disorder identified by developmental delays and difficulties in the ability to produce speech.
An impairment in expressive language development.
Expressive language disorder (DSM 315.31) is a communication disorder which is characterised by having a limited vocabulary and grasp of grammar. ...
en.wikipedia.org/wiki/Expressive language disorder
Expressive language disorder is generally a childhood disorder. There are two types of ELD.
The developmental type- does not have a known cause and generally appears at that time a child is learning to talk.
The Acquired type- is caused by damage to the brain. It occurs suddenly after events such as stroke or traumatic head injury. And it can occur at any age.
There is no known cause of developmental expressive language disorder. Research is ongoing to determine which biological or environmental factors may be the cause.
Acquired expressive language disorder is caused by damage to the brain. Damage can be sustained during a stroke, or as the result of traumatic head injury, seizures, or other medical conditions. The way in which acquired expressive language disorder manifests itself in a specific person depends on which parts of the brain are immured and how badly they are damaged.
ELD- is characterized by a child having difficulty expressing himself/herself using speech. The signs and symptoms vary drastically from child to child. The child does not have problems with the pronunciation or words, as occurs in phonological disorder. The child does not have problems putting sentences together coherently, using proper grammar, recalling the appropriate word to use, or other similar problems. A child with ELD is not able to communicate thoughts, needs, or wants at the same level or with the same complexity as his or her peers. The child often has a smaller vocabulary than his/her peers.
- they have the same ability to understand speech as their peers, and have the same level of intelligence. Therefore, a child with this disorder may understand words that he/she cannot use in sentences. The child may understand complex spoken sentences and be able to carry out intricate instructions.
Some children do not properly use pronouns, or leave out functional words such as “is” or “the”. Other children cannot recall words that they want to use in the sentence and substitute general words such as “thing” or “stuff”. Some children cannot organize their sentences so that the sentences are easy to understand. These children do comprehend the material they are trying to express they just cannot create the appropriate sentences with which to express their thoughts.
Is a relatively common childhood disorder. Language delays occur in 10-15% of children under age three, and in 3-7% of school-age children. ELD is more common in boys than in girls. Studies suggest that developmental ELD occurs two to five times more often in boys as girls. The developmental form of the disorder is far more common than acquired type.
Children must be performing below their peers at tasks that require communication in the form of speech. This can be hard to determine because it must be shown that an individual understands the material , but cannot express that comprehension. Therefore, non-verbal tests must be used in addition to tests that require spoken answers. Hearing should also be evaluated, because children who do not hear well may have problems putting together sentences similar to children with expressive language disorder. In children who are mildly hearing impaired, the problem can often be resolved by using hearing aids to enhance the child’s hearing. Also, children who speak a language other than English in the home should be tested in that language if possible. The child’s ability to communicate in English may be the problem, not the child’s ability to communicate in general.
The Diagnostic and Statistical of Manual of Mental Disorders.
- The first is that the child communicates using speech at a level that is less developed than expected for his/her intelligence and ability to understand spoken language. This problem with communication using speech must create difficulties for the child in everyday life or in achieving goals. The child must understand what is being said at a level that is age-appropriate, or at a developmental level consistent with the child’s. Otherwise the diagnoses should be mixed receptive expressive language disorder. If the child has mental retardation, poor hearing, or other problems, the difficulties with speech must be greater than is generally associated with the handicaps that the child has.
There are two types of treatment used for expressive language disorder. The first involves the child working one-on-one with speech therapist on a regular schedule and practicing speech and communication skills. The second type of treatment involves the child’s parents and teachers working together to incorporate spoken language that the child needs into everyday activities and play. Both of these kinds of treatment can be effective, and are often used together.
The developmental form of ELD generally has a good prognosis. Most children develop normal or nearly normal language skills by high school. In some cases, minor problems with expressive language disorder has a prognosis that depends on the nature and location of the brain injury. Some people get their language skills back over days and months. For others, it takes years, and some people never fully recover expressive language function.
There is no known way to prevent developmental expressive language disorder. Because acquired language disorder is caused by damage to the brain, anything that would help to prevent brain damage may help to prevent that type of the disorder. This can include such things ranging from the lowering cholesterol in order to prevent stroke to wearing a bicycle helmet to prevent traumatic brain injury.
Posted byDoc Junhel at 3:53 PM
Ethical theories represent the grand ideas on which guiding principles are based. They attempt to be coherent and systematic, striving to answer the fundamental practical ethical questions:
What ought I do?
How ought I live?
Generally ethical principles stem from ethical theories, and when defending a particular action, ethicists normally appeal to these principles, not the underlying theory. Ethical traditions stretch back to earliest recorded history. Separate bodies of ethics, often not encompassing a true theory but rather a general system, were developed in India and China, and within the Jewish, Christian, Islamic, and Buddhist and Hindu religions. All of these theories represent altruistic, rather than egoistic, attitudes towards mankind. Some of the most commonly cited ethical theories include the following:
The system of natural law, often attributed to Aristotle, posits that man should live life according to an inherent human nature. It can be contrasted with man-made, or judicial, law, but they are similar in that both may change over time, despite the frequent claim that natural law is immutable, often tying it to particular religious beliefs.
Deontology holds that the most important aspects of our lives are governed by certain unbreakable moral rules. Deontologists hold that these rules may not be broken, even if breaking them may improve an outcome. In other words, they may do the "right" thing, even though the consequences of that action may not be "good." The famous philosopher, Immanuel Kant is often identified with this theory. One example of a list of "unbreakable" rules is the Ten Commandments.
One of the more functional and commonly used theories, utilitarianism, sometimes called consequentialism or teleology, basically promotes good or valued ends, rather than using the right means. This theory instructs adherents to work for those outcomes that will give the most advantage to the majority of those affected in the most impartial way possible. (Simplistically, this theory advocates achieving the greatest good for the greatest number of people.) It is often advocated as the basis for broad social policies.
The virtue theory asks what a "good person" would do in specific real-life situations. This recently revived theory stems from the character traits discussed by Aristotle, Plato, and Thomas Aquinas. They discuss such timeless and cross-cultural virtues as courage, temperance, wisdom, justice, faith, and charity.
Values And Principles
Values are the standards by which we judge human behavior. They are, in other words, moral rules, promoting those things thought of as good and minimizing or avoiding those things thought of as bad. We usually learn these values at an early age, from observing behavior and through secular (including professional) and religious education. Societal institutions incorporate and promulgate values often attempting to make old values rigid, even in a changing society. In a pluralistic society, clinicians often treat subjects having multiple and differing value systems, and they must be sensitive to others’ beliefs and traditions.
Ethical values stem from ethical principles. Ethical principles are action guides derived from ethical theories. Each of these principles consists of various moral rules, which are our learned values. For example, the values of dealing honestly with patients; fully informing patients before procedures, therapy, or being involved in research; and respecting the patient’s personal values are all subsumed under the principle of autonomy or respect for persons.
Although each person is entitled (and perhaps even required) to have a personal system of values, there are certain values that have become generally accepted by the medical community, courts, legislatures, and society at large. A respect for patients (often described as patient autonomy) has been considered so fundamental that it is often given overriding importance. Although some groups disagree about each of the generally accepted values, this dissension has not affected their application to medical care.
Assessing Patient Values
A key to making ethical decisions at the bedside is to know what the patient’s values are. In patients too young or incompetent to express their values, it may be necessary for physicians to make general assumptions about what the normal person would want in a specific situation or to rely on surrogate decision making. With patients who are able to communicate, however, care must be taken to discover what their own uncoerced values really are.
A typical ethically dangerous scenario is with a patient who refuses lifesaving medical intervention "on religious grounds." Typically, the spouse is at the bedside, does most of the talking, and may be influencing the patient’s decision. In those cases, it is incumbent on the clinician to question the patient alone to assess his or her real values.
What is gene testing? How does it work?
Gene tests (also called DNA-based tests), the newest and most sophisticated of the techniques used to test for genetic disorders, involve direct examination of the DNA molecule itself. Other genetic tests include biochemical tests for such gene products as enzymes and other proteins and for microscopic examination of stained or fluorescent chromosomes. Genetic tests are used for several reasons, including:
- carrier screening, which involves identifying unaffected individuals who carry one copy of a gene for a disease that requires two copies for the disease to be expressed
- preimplantation genetic diagnosis (see the side bar, Screening Embryos for Disease)
- prenatal diagnostic testing
- newborn screening
- presymptomatic testing for predicting adult-onset disorders such as Huntington's disease
- presymptomatic testing for estimating the risk of developing adult-onset cancers and Alzheimer's disease
- confirmational diagnosis of a symptomatic individual
- forensic/identity testing
In gene tests, scientists scan a patient's DNA sample for mutated sequences. A DNA sample can be obtained from any tissue, including blood. For some types of gene tests, researchers design short pieces of DNA called probes, whose sequences are complementary to the mutated sequences. These probes will seek their complement among the three billion base pairs of an individual's genome. If the mutated sequence is present in the patient's genome, the probe will bind to it and flag the mutation. Another type of DNA testing involves comparing the sequence of DNA bases in a patient's gene to a normal version of the gene. Cost of testing can range from hundreds to thousands of dollars, depending on the sizes of the genes and the numbers of mutations tested.
Gene testing already has dramatically improved lives. Some tests are used to clarify a diagnosis and direct a physician toward appropriate treatments, while others allow families to avoid having children with devastating diseases or identify people at high risk for conditions that may be preventable. Aggressive monitoring for and removal of colon growths in those inheriting a gene for familial adenomatous polyposis, for example, has saved many lives. On the horizon is a gene test that will provide doctors with a simple diagnostic test for a common iron-storage disease, transforming it from a usually fatal condition to a treatable one.
Commercialized gene tests for adult-onset disorders such as Alzheimer's disease and some cancers are the subject of most of the debate over gene testing. These tests are targeted to healthy (presymptomatic) people who are identified as being at high risk because of a strong family medical history for the disorder. The tests give only a probability for developing the disorder. One of the most serious limitations of these susceptibility tests is the difficulty in interpreting a positive result because some people who carry a disease-associated mutation never develop the disease. Scientists believe that these mutations may work together with other, unknown mutations or with environmental factors to cause disease.
A limitation of all medical testing is the possibility for laboratory errors. These might be due to sample misidentification, contamination of the chemicals used for testing, or other factors.
Many in the medical establishment feel that uncertainties surrounding test interpretation, the current lack of available medical options for these diseases, the tests' potential for provoking anxiety, and risks for discrimination and social stigmatization could outweigh the benefits of testing.
Currently, more than 1000 genetic tests are available from testing laboratories. Some gene tests available in the past few years from clinical genetics laboratories appear below. Test names and a description of the diseases or symptoms are in parentheses. Susceptibility tests, noted by an asterisk, provide only an estimated risk for developing the disorder. Contact GeneTests for comprehensive information on test availability and genetic testing facilities.
Some Currently Available DNA-Based Gene Tests
- Alpha-1-antitrypsin deficiency (AAT; emphysema and liver disease)
- Amyotrophic lateral sclerosis (ALS; Lou Gehrig's Disease; progressive motor function loss leading to paralysis and death)
- Alzheimer's disease* (APOE; late-onset variety of senile dementia)
- Ataxia telangiectasia (AT; progressive brain disorder resulting in loss of muscle control and cancers)
- Gaucher disease (GD; enlarged liver and spleen, bone degeneration)
- Inherited breast and ovarian cancer* (BRCA 1 and 2; early-onset tumors of breasts and ovaries)
- Hereditary nonpolyposis colon cancer* (CA; early-onset tumors of colon and sometimes other organs)
- Central Core Disease (CCD; mild to severe muscle weakness)
- Charcot-Marie-Tooth (CMT; loss of feeling in ends of limbs)
- Congenital adrenal hyperplasia (CAH; hormone deficiency; ambiguous genitalia and male pseudohermaphroditism)
- Cystic fibrosis (CF; disease of lung and pancreas resulting in thick mucous accumulations and chronic infections)
- Duchenne muscular dystrophy/Becker muscular dystrophy (DMD; severe to mild muscle wasting, deterioration, weakness)
- Dystonia (DYT; muscle rigidity, repetitive twisting movements)
- Emanuel Syndrome (severe mental retardation, abnormal development of the head, heart and kidney problems)
- Fanconi anemia, group C (FA; anemia, leukemia, skeletal deformities)
- Factor V-Leiden (FVL; blood-clotting disorder)
- Fragile X syndrome (FRAX; leading cause of inherited mental retardation)
- Galactosemia (GALT; metabolic disorder affects ability to metabolize galactose)
- Hemophilia A and B (HEMA and HEMB; bleeding disorders)
- Hereditary Hemochromatosis (HFE; excess iron storage disorder)
- Huntington's disease (HD; usually midlife onset; progressive, lethal, degenerative neurological disease)
- Marfan Syndrome (FBN1; connective tissue disorder; tissues of ligaments, blood vessel walls, cartilage, heart valves and other structures abnormally weak)
- Mucopolysaccharidosis (MPS; deficiency of enzymes needed to break down long chain sugars called glycosaminoglycans; corneal clouding, joint stiffness, heart disease, mental retardation)
- Myotonic dystrophy (MD; progressive muscle weakness; most common form of adult muscular dystrophy)
- Neurofibromatosis type 1 (NF1; multiple benign nervous system tumors that can be disfiguring; cancers)
- Phenylketonuria (PKU; progressive mental retardation due to missing enzyme; correctable by diet)
- Polycystic Kidney Disease (PKD1, PKD2; cysts in the kidneys and other organs)
- Adult Polycystic Kidney Disease (APKD; kidney failure and liver disease)
- Prader Willi/Angelman syndromes (PW/A; decreased motor skills, cognitive impairment, early death)
- Sickle cell disease (SS; blood cell disorder; chronic pain and infections)
- Spinocerebellar ataxia, type 1 (SCA1; involuntary muscle movements, reflex disorders, explosive speech)
- Spinal muscular atrophy (SMA; severe, usually lethal progressive muscle-wasting disorder in children)
- Tay-Sachs Disease (TS; fatal neurological disease of early childhood; seizures, paralysis)
- Thalassemias (THAL; anemias - reduced red blood cell levels)
- Timothy Syndrome (CACNA1C; characterized by severe cardiac arrhythmia, webbing of the fingers and toes called syndactyly, autism)
Currently in the
In most cases, an individual will have to contact his or her insurance provider to see if genetic tests, which cost between $200 and $3000, are covered. Usually insurance companies do not cover genetic tests, those that do will have access to the results. Insured persons would need to decide whether they would want the insurance company to have this information. States have a patchwork of genetic-information nondiscrimination laws, none of them comprehensive. Existing state laws differ in coverage, protections afforded, and enforcement schemes. The National Conference of State Legislatures provides a listing of current legislation regarding genetic information and health insurance. The recent marketing of genetic test kits directly to consumers, may lead to an increase in demand for insurance coverage. See the Genetics and Health Insurance (PDF) policy brief from the National Conference of State Legislatures for more information.
Genes, which are carried on chromosomes, are the basic physical and functional units of heredity. Genes are specific sequences of bases that encode instructions on how to make proteins. Although genes get a lot of attention, it’s the proteins that perform most life functions and even make up the majority of cellular structures. When genes are altered so that the encoded proteins are unable to carry out their normal functions, genetic disorders can result.
Gene therapy is a technique for correcting defective genes responsible for disease development. Researchers may use one of several approaches for correcting faulty genes:
- A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. This approach is most common.
- An abnormal gene could be swapped for a normal gene through homologous recombination.
- The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal function.
- The regulation (the degree to which a gene is turned on or off) of a particular gene could be altered.
In most gene therapy studies, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene. A carrier molecule called a vector must be used to deliver the therapeutic gene to the patient's target cells. Currently, the most common vector is a virus that has been genetically altered to carry normal human DNA. Viruses have evolved a way of encapsulating and delivering their genes to human cells in a pathogenic manner. Scientists have tried to take advantage of this capability and manipulate the virus genome to remove disease-causing genes and insert therapeutic genes.
Target cells such as the patient's liver or lung cells are infected with the viral vector. The vector then unloads its genetic material containing the therapeutic human gene into the target cell. The generation of a functional protein product from the therapeutic gene restores the target cell to a normal state. See a diagram depicting this process.
Some of the different types of viruses used as gene therapy vectors:
- Retroviruses - A class of viruses that can create double-stranded DNA copies of their RNA genomes. These copies of its genome can be integrated into the chromosomes of host cells. Human immunodeficiency virus (HIV) is a retrovirus.
- Adenoviruses - A class of viruses with double-stranded DNA genomes that cause respiratory, intestinal, and eye infections in humans. The virus that causes the common cold is an adenovirus.
- Adeno-associated viruses - A class of small, single-stranded DNA viruses that can insert their genetic material at a specific site on chromosome 19.
- Herpes simplex viruses - A class of double-stranded DNA viruses that infect a particular cell type, neurons. Herpes simplex virus type 1 is a common human pathogen that causes cold sores.
Besides virus-mediated gene-delivery systems, there are several nonviral options for gene delivery. The simplest method is the direct introduction of therapeutic DNA into target cells. This approach is limited in its application because it can be used only with certain tissues and requires large amounts of DNA.
Another nonviral approach involves the creation of an artificial lipid sphere with an aqueous core. This liposome, which carries the therapeutic DNA, is capable of passing the DNA through the target cell's membrane.
Therapeutic DNA also can get inside target cells by chemically linking the DNA to a molecule that will bind to special cell receptors. Once bound to these receptors, the therapeutic DNA constructs are engulfed by the cell membrane and passed into the interior of the target cell. This delivery system tends to be less effective than other options.
Researchers also are experimenting with introducing a 47th (artificial human) chromosome into target cells. This chromosome would exist autonomously alongside the standard 46 --not affecting their workings or causing any mutations. It would be a large vector capable of carrying substantial amounts of genetic code, and scientists anticipate that, because of its construction and autonomy, the body's immune systems would not attack it. A problem with this potential method is the difficulty in delivering such a large molecule to the nucleus of a target cell.
The Food and Drug Administration (FDA) has not yet approved any human gene therapy product for sale. Current gene therapy is experimental and has not proven very successful in clinical trials. Little progress has been made since the first gene therapy clinical trial began in 1990. In 1999, gene therapy suffered a major setback with the death of 18-year-old Jesse Gelsinger. Jesse was participating in a gene therapy trial for ornithine transcarboxylase deficiency (OTCD). He died from multiple organ failures 4 days after starting the treatment. His death is believed to have been triggered by a severe immune response to the adenovirus carrier.
Another major blow came in January 2003, when the FDA placed a temporary halt on all gene therapy trials using retroviral vectors in blood stem cells. FDA took this action after it learned that a second child treated in a French gene therapy trial had developed a leukemia-like condition. Both this child and another who had developed a similar condition in August 2002 had been successfully treated by gene therapy for X-linked severe combined immunodeficiency disease (X-SCID), also known as "bubble baby syndrome."
FDA's Biological Response Modifiers Advisory Committee (BRMAC) met at the end of February 2003 to discuss possible measures that could allow a number of retroviral gene therapy trials for treatment of life-threatening diseases to proceed with appropriate safeguards. In April of 2003 the FDA eased the ban on gene therapy trials using retroviral vectors in blood stem cells.
- Short-lived nature of gene therapy - Before gene therapy can become a permanent cure for any condition, the therapeutic DNA introduced into target cells must remain functional and the cells containing the therapeutic DNA must be long-lived and stable. Problems with integrating therapeutic DNA into the genome and the rapidly dividing nature of many cells prevent gene therapy from achieving any long-term benefits. Patients will have to undergo multiple rounds of gene therapy.
- Immune response - Anytime a foreign object is introduced into human tissues, the immune system is designed to attack the invader. The risk of stimulating the immune system in a way that reduces gene therapy effectiveness is always a potential risk. Furthermore, the immune system's enhanced response to invaders it has seen before makes it difficult for gene therapy to be repeated in patients.
- Problems with viral vectors - Viruses, while the carrier of choice in most gene therapy studies, present a variety of potential problems to the patient --toxicity, immune and inflammatory responses, and gene control and targeting issues. In addition, there is always the fear that the viral vector, once inside the patient, may recover its ability to cause disease.
- Multigene disorders - Conditions or disorders that arise from mutations in a single gene are the best candidates for gene therapy. Unfortunately, some the most commonly occurring disorders, such as heart disease, high blood pressure, Alzheimer's disease, arthritis, and diabetes, are caused by the combined effects of variations in many genes. Multigene or multifactorial disorders such as these would be especially difficult to treat effectively using gene therapy. For more information on different types of genetic disease, see Genetic Disease Information.
· Results of world's first gene therapy for inherited blindness show sight improvement. 28 April 2008.
Previous information on this trial (May 1, 2007): A team of British doctors from Moorfields Eye Hospital and University College in London conduct first human gene therapy trials to treat Leber's congenital amaurosis, a type of inherited childhood blindness caused by a single abnormal gene. The procedure has already been successful at restoring vision for dogs. This is the first trial to use gene therapy in an operation to treat blindness in humans. See Doctors Test Gene Therapy to Treat Blindness at www.reuters.com.
- A combination of two tumor suppressing genes delivered in lipid-based nanoparticles drastically reduces the number and size of human lung cancer tumors in mice during trials conducted by researchers from The University of Texas M. D. Anderson Cancer Center and the University of Texas Southwestern Medical Center. See Dual Gene Therapy Suppresses Lung Cancer in Preclinical Test at www.newswise.com (January 11, 2007).
- Researchers at the National Cancer Institute (NCI), part of the National Institutes of Health, successfully reengineer immune cells, called lymphocytes, to target and attack cancer cells in patients with advanced metastatic melanoma. This is the first time that gene therapy is used to successfully treat cancer in humans. See New Method of Gene Therapy Alters Immune Cells for Treatment of Advanced Melanoma at www.cancer.gov (August 30, 2006).
- Gene therapy is effectively used to treat two adult patients for a disease affecting nonlymphocytic white blood cells called myeloid cells. Myeloid disorders are common and include a variety of bone marrow failure syndromes, such as acute myeloid leukemia. The study is the first to show that gene therapy can cure diseases of the myeloid system. See Gene Therapy Appears to Cure Myeloid Blood Diseases In Groundbreaking International Study at www.cincinnatichildrens.org (March 31, 2006).
- Gene Therapy cures deafness in guinea pigs. Each animal had been deafened by destruction of the hair cells in the cochlea that translate sound vibrations into nerve signals. A gene, called Atoh1, which stimulates the hair cells' growth, was delivered to the cochlea by an adenovirus. The genes triggered re-growth of the hair cells and many of the animals regained up to 80% of their original hearing thresholds. This study, which many pave the way to human trials of the gene, is the first to show that gene therapy can repair deafness in animals. See Gene Therapy is First Deafness 'Cure' at NewScientist.com (February 11, 2005).
Universityof California, , research team gets genes into the brain using liposomes coated in a polymer call polyethylene glycol (PEG). The transfer of genes into the brain is a significant achievement because viral vectors are too big to get across the "blood-brain barrier." This method has potential for treating Parkinson's disease. See Undercover Genes Slip into the Brain at NewScientist.com (March 20, 2003). Los Angeles
- RNA interference or gene silencing may be a new way to treat
's. Short pieces of double-stranded RNA (short, interfering RNAs or siRNAs) are used by cells to degrade RNA of a particular sequence. If a siRNA is designed to match the RNA copied from a faulty gene, then the abnormal protein product of that gene will not be produced. See Gene Therapy May Switch off Huntington's at NewScientist.com (March 13, 2003). Huntington
- New gene therapy approach repairs errors in messenger RNA derived from defective genes. Technique has potential to treat the blood disorder thalassaemia, cystic fibrosis, and some cancers. See Subtle Gene Therapy Tackles Blood Disorder at NewScientist.com (October 11, 2002).
- Gene therapy for treating children with X-SCID (sever combined immunodeficiency) or the "bubble boy" disease is stopped in
when the treatment causes leukemia in one of the patients. See 'Miracle' Gene Therapy Trial Halted at NewScientist.com (October 3, 2002). France
- Researchers at
and Copernicus Therapeutics are able to create tiny liposomes 25 nanometers across that can carry therapeutic DNA through pores in the nuclear membrane. See DNA Nanoballs Boost Gene Therapy at NewScientist.com (May 12, 2002). Case Western Reserve University
- Sickle cell is successfully treated in mice. See Murine Gene Therapy Corrects Symptoms of Sickle Cell Disease from March 18, 2002, issue of The Scientist.
--Some Questions to Consider...
- What is normal and what is a disability or disorder, and who decides?
- Are disabilities diseases? Do they need to be cured or prevented?
- Does searching for a cure demean the lives of individuals presently affected by disabilities?
- Is somatic gene therapy (which is done in the adult cells of persons known to have the disease) more or less ethical than germline gene therapy (which is done in egg and sperm cells and prevents the trait from being passed on to further generations)? In cases of somatic gene therapy, the procedure may have to be repeated in future generations.
- Preliminary attempts at gene therapy are exorbitantly expensive. Who will have access to these therapies? Who will pay for their use?
Genetic counselors are health professionals with specialized graduate degrees and experience in the areas of medical genetics and counseling. Most enter the field from a variety of disciplines, including biology, genetics, nursing, psychology, public health, and social work.
Genetic counselors work as members of a healthcare team, providing information and support to families who have members with birth defects or genetic disorders and to families who may be at risk for a variety of inherited conditions. They identify families at risk, investigate the problem present in the family, interpret information about the disorder, analyze inheritance patterns and risks of recurrence, and review available options with the family.
Genetic counselors also provide supportive counseling to families, serve as patient advocates, and refer individuals and families to community or state support services. They serve as educators and resource people for other healthcare professionals and for the general public. Some counselors also work in administrative capacities. Many engage in research activities related to the field of medical genetics and genetic counseling.
Societal Concerns Arising from the New Genetics
Fairness in the use of genetic information by insurers, employers, courts, schools, adoption agencies, and the military, among others.
Who should have access to personal genetic information, and how will it be used?
For more on this topic, see the Privacy and Legislation page in this ELSI suite.
Privacy and confidentiality of genetic information.
Who owns and controls genetic information?
For more on this topic, see the Privacy and Legislation page in this ELSI suite.
Psychological impact and stigmatization due to an individual's genetic differences.
How does personal genetic information affect an individual and society's perceptions of that individual?
How does genomic information affect members of minority communities?
For more on this topic, see the Minorities, Race, and Genetics and Genetic Anthropology, Ancestry, and Ancient Human Migration pages in this ELSI suite.
Reproductive issues including adequate informed consent for complex and potentially controversial procedures, use of genetic information in reproductive decision making, and reproductive rights.
Do healthcare personnel properly counsel parents about the risks and limitations of genetic technology?
How reliable and useful is fetal genetic testing?
What are the larger societal issues raised by new reproductive technologies?
For more on this topic, see the Gene Testing page in this ELSI suite.
Clinical issues including the education of doctors and other health service providers, patients, and the general public in genetic capabilities, scientific limitations, and social risks; and implementation of standards and quality-control measures in testing procedures.
How will genetic tests be evaluated and regulated for accuracy, reliability, and utility? (Currently, there is little regulation at the federal level.)
How do we prepare healthcare professionals for the new genetics?
How do we prepare the public to make informed choices?
How do we as a society balance current scientific limitations and social risk with long-term benefits?
Uncertainties associated with gene tests for susceptibilities and complex conditions (e.g., heart disease) linked to multiple genes and gene-environment interactions.
Should testing be performed when no treatment is available?
Should parents have the right to have their minor children tested for adult-onset diseases?
Are genetic tests reliable and interpretable by the medical community?
Conceptual and philosophical implications regarding human responsibility, free will vs genetic determinism, and concepts of health and disease.
Do people's genes make them behave in a particular way?
Can people always control their behavior?
What is considered acceptable diversity?
Where is the line between medical treatment and enhancement?
For more on this topic, see the Behavioral Genetics page in this ELSI suite.
Health and environmental issues concerning genetically modified foods (GM) and microbes.
Are GM foods and other products safe to humans and the environment?
How will these technologies affect developing nations' dependence on the West?
For more on this topic, see the Genetically Modified Foods page in this ELSI suite.
Commercialization of products including property rights (patents, copyrights, and trade secrets) and accessibility of data and materials.
Who owns genes and other pieces of DNA?
Will patenting DNA sequences limit their accessibility and development into useful products?
Posted byDoc Junhel at 3:51 PM