So is high blood pressure really genetic? Yes, hypertension is inherited, but this does not automatically mean that you will develop it yourself if most of your family members have it. However, it is not yet known exactly how it is inherited. Some characteristics and some rare diseases can be caused by inheriting single genes. But it is also known, with certain rare exceptions, that high blood pressure is hardly ever inherited in this simple way.
In most cases, high blood pressure depends on the interaction of various inheritable factors, which may only become activated only in the presence of certain environmental conditions. This is known as genotype-environment interaction. The most important of these conditions is probably prematurity, obesity in adolescence and as a young adult, sodium intake and alcohol intake particularly in early adulthood. In any case, however, it is pointless to argue about nature versus nurture, or environment versus inheritance. It is more essential to acknowledge that there may be a possibility pf developing high blood pressure and that one should be sensible about what one eats and drinks and the amount of exercise that one does.
High blood pressure may begin in childhood. Nevertheless, knowing this is of little practical use. There is already evidence that weight control in case of childhood obesity, perhaps on a vegetarian diet, may be a good prophylactic against later high blood pressure in adulthood, but not much data to support any other specific preventive actions. Generally, screening children for blood pressure is essentially a method of research, not a useful procedure in general practice and, if done at all, it must be done by highly trained medical personnel. The fact that high blood pressure begins with inheritance or in childhood does not mean that you actually had high blood pressure in childhood - just that the tendency for you to develop it as you grow older is already there. Screening is not useful for finding the equally rare cases of secondary high blood pressure, where blood pressure rises rapidly over a short period and is caused by some other illness, which is usually a kidney disorder. Knowing that a child has high blood pressure is not a very useful predictor of what will happen as the child ages. Although there is a general tendency for newborns with high blood pressure to become adults with hypertension, the association remains debatable. In a study of fourteen year olds with untreated high blood pressure (170/100 mmHg) examined twenty years after, only 17% had hypertension twenty years later.
The causes of high blood pressure in people in their 30s are generally the same as in those individuals who are older, regardless of smoking and drinking behavior. In such cases, it should be noted that most causes of high blood pressure in middle age and later life are still uncertain. The main difference is that in younger adults, there are more cases of secondary high blood pressure caused by other conditions, often those disorders involving the kidney and the adrenal glands. Everyone aged under 40 found to have high blood pressure should be referred to a consultant for individual examinations to see if it is being caused by such conditions. For the occasional person with very high blood pressure (sustained diastolic pressure of 120 mmHg or more), physicians should still monitor these individuals closely. For most people in this age bracket with raised blood pressure but below this level, routine referral for these medical examinations is not necessary - providing that the physician organizes a few simple tests and make a careful evaluation of responses to treatment. Most people who then need a medical specialist, not just for routine tests but a comprehensive and detailed search for the causes of raised blood pressure, can then usually be identified so that these individuals can get the attention they deserve, as many of these underlying causes are very difficult to find.
Chemical Imbalance in Brain & Schizophrenia
A popular theory is that schizophrenia is caused by an imbalance of neurotransmitters in the brain. Neurotransmitters (pronounced NOOR-oh-TRANZ-mit-urz) are chemicals that carry electrical messages between nerve cells. Too much of a neurotransmitter, or too little, may account for various mental disorders, including schizophrenia.
There is still no consensus (agreement) as to which, if any, of these theories is correct, or whether the disease is caused by a combination of factors.
There is still no consensus (agreement) as to which, if any, of these theories is correct, or whether the disease is caused by a combination of factors.
Schizophrenia
Schizophrenia (pronounced skit-suh-FREH-nee-uh) is a psychotic disorder or group of psychotic disorders that cause a patient to lose touch with reality. It is marked by severely impaired reasoning and emotional instability and can cause violent behavior.
Schizophrenic patients are often unable to make sense of the signals they receive from the world around them. They imagine objects and events to be very different from what they really are. If untreated, most people with schizophrenia gradually withdraw from the outside world.
Exactly what schizophrenia is has been the source of considerable disagreement among psychiatrists (doctors who deal with mental disorders). There is some thought that the disease psychiatrists call schizophrenia is actually a number of different conditions classified under a single heading.
Schizophrenic patients are often unable to make sense of the signals they receive from the world around them. They imagine objects and events to be very different from what they really are. If untreated, most people with schizophrenia gradually withdraw from the outside world.
Exactly what schizophrenia is has been the source of considerable disagreement among psychiatrists (doctors who deal with mental disorders). There is some thought that the disease psychiatrists call schizophrenia is actually a number of different conditions classified under a single heading.
DNA nanotechnology
DNA nanotechnology uses the unique molecular recognition properties of DNA and other nucleic acids to create self-assembling branched DNA complexes with useful properties.[124] DNA is thus used as a structural material rather than as a carrier of biological information. This has led to the creation of two-dimensional periodic lattices (both tile-based as well as using the "DNA origami" method) as well as three-dimensional structures in the shapes of polyhedra.[125] Nanomechanical devices and algorithmic self-assembly have also been demonstrated,[126] and these DNA structures have been used to template the arrangement of other molecules such as gold nanoparticles and streptavidin proteins
Sense and antisense
A DNA sequence is called "sense" if its sequence is the same as that of a messenger RNA copy that is translated into protein.[19] The sequence on the opposite strand is called the "antisense" sequence. Both sense and antisense sequences can exist on different parts of the same strand of DNA (i.e. both strands contain both sense and antisense sequences). In both prokaryotes and eukaryotes, antisense RNA sequences are produced, but the functions of these RNAs are not entirely clear.[20] One proposal is that antisense RNAs are involved in regulating gene expression through RNA-RNA base pairing.[21]
A few DNA sequences in prokaryotes and eukaryotes, and more in plasmids and viruses, blur the distinction between sense and antisense strands by having overlapping genes.[22] In these cases, some DNA sequences do double duty, encoding one protein when read along one strand, and a second protein when read in the opposite direction along the other strand. In bacteria, this overlap may be involved in the regulation of gene transcription,[23] while in viruses, overlapping genes increase the amount of information that can be encoded within the small viral genome.
A few DNA sequences in prokaryotes and eukaryotes, and more in plasmids and viruses, blur the distinction between sense and antisense strands by having overlapping genes.[22] In these cases, some DNA sequences do double duty, encoding one protein when read along one strand, and a second protein when read in the opposite direction along the other strand. In bacteria, this overlap may be involved in the regulation of gene transcription,[23] while in viruses, overlapping genes increase the amount of information that can be encoded within the small viral genome.
Chromosome diseases:
These diseases are caused by a major error in the DNA, with an entire chromosome having a problem. Chromosomes have hundreds and thousands of genes, so these diseases have major errors in the DNA code. The most common example is down syndrome.
About inheritance and genetics:
Inheritance of Nervous system disorders refers to whether the condition is inherited from your parents or "runs" in families. The level of inheritance of a condition depends on how important genetics are to the disease. Strongly genetic diseases are usually inherited, partially genetic diseases are sometimes inherited, and non-genetic diseases are not inherited. For general information,
Inheritance and Genetics of Nervous system disorders
Genetics of Nervous system disorders: Several diseases that directly affect the nervous system have a genetic component: some are due to a mutation in a single gene, others are proving to have a more complex mode of inheritance. As our understanding of the pathogenesis of neurodegenerative disorders deepens, common themes begin to emerge: Alzheimer brain plaques and the inclusion bodies found in Parkinson disease contain at least one common component, while Huntington disease, fragile X syndrome and spinocerebellar atrophy are all 'dynamic mutation' diseases in which there is an expansion of a DNA repeat sequence. Apoptosis is emerging as one of the molecular mechanisms invoked in several neurodegenerative diseases, as are other, specific, intracellular signaling events. The biosynthesis of myelin and the regulation of cholesterol traffic also figure in Charcot-Marie-Tooth and Neimann-Pick disease, respectively. (Source: Genes and Disease by the National Center for Biotechnology)
The Structure of Double-Stranded Dna
Structure of a DNA quadruplex
As mentioned above, the two individual strands are held together by hydrogen bonds between individual T·A and C·G base pairs. In DNA, the distance between the atoms involved is 2.8 to 2.95 angstroms (10−10 meters). While individually weak, the large number of hydrogen bonds along a DNA chain provides sufficient stability to hold the two strands together.
The stabilization of duplex (double-stranded) DNA is also dependent on base stacking. The planar, rigid bases stack on top of one another, much like a stack of coins. Since the two purine.pyrimidine pairs (A.T and C.G) have the same width, the bases stack in a rather uniform fashion. Stacking near the center of the helix affords protection from chemical and environmental attack. Both hydrophobic interactions and van der Waal's forces hold bases together in stacking interactions. About half the stability of the DNA helix comes from hydrogen bonding, while base stacking provides much of the rest.Double-stranded DNA in its canonical B-form is a right-handed helix formed by two individual DNA strands aligned in an antiparallel fashion (a right-handed helix, when viewed on end, twists clockwise going away from the viewer). Antiparallel DNA has the two strands organized in the opposite polarity, with one strand oriented in the 5′-3′ direction and the other oriented in the 3′-5′ direction.
In the right-handed B-DNA double helix, the stacked base pairs are separated by about 3.24 angstroms with 10.5 base pairs forming one helical turn (360°), which is 35.7 angstroms in length. Two successive base pairs, therefore, are rotated about 34.3° with respect to each other. The width of the helix is 20 angstroms. An idealized model of the double helix is shown in Figure 3. As can be seen, the organization of the bases creates a major groove and a minor groove.
Adenine and thymine are said to be complementary as are cytosine and guanine. Complementary means "matching opposite." The shapes and charges of adeninne and thymine complement each other, so that they attract one another and link up (as do cytosine and guanine). Indeed, one entire strand of duplex DNA is complementary to the opposing strand. During replication, the two strands unwindand each serves as a template for formation of new complementary strand, so that replication ends with two exact double-stranded copies.
As mentioned above, the two individual strands are held together by hydrogen bonds between individual T·A and C·G base pairs. In DNA, the distance between the atoms involved is 2.8 to 2.95 angstroms (10−10 meters). While individually weak, the large number of hydrogen bonds along a DNA chain provides sufficient stability to hold the two strands together.
The stabilization of duplex (double-stranded) DNA is also dependent on base stacking. The planar, rigid bases stack on top of one another, much like a stack of coins. Since the two purine.pyrimidine pairs (A.T and C.G) have the same width, the bases stack in a rather uniform fashion. Stacking near the center of the helix affords protection from chemical and environmental attack. Both hydrophobic interactions and van der Waal's forces hold bases together in stacking interactions. About half the stability of the DNA helix comes from hydrogen bonding, while base stacking provides much of the rest.Double-stranded DNA in its canonical B-form is a right-handed helix formed by two individual DNA strands aligned in an antiparallel fashion (a right-handed helix, when viewed on end, twists clockwise going away from the viewer). Antiparallel DNA has the two strands organized in the opposite polarity, with one strand oriented in the 5′-3′ direction and the other oriented in the 3′-5′ direction.
In the right-handed B-DNA double helix, the stacked base pairs are separated by about 3.24 angstroms with 10.5 base pairs forming one helical turn (360°), which is 35.7 angstroms in length. Two successive base pairs, therefore, are rotated about 34.3° with respect to each other. The width of the helix is 20 angstroms. An idealized model of the double helix is shown in Figure 3. As can be seen, the organization of the bases creates a major groove and a minor groove.
Adenine and thymine are said to be complementary as are cytosine and guanine. Complementary means "matching opposite." The shapes and charges of adeninne and thymine complement each other, so that they attract one another and link up (as do cytosine and guanine). Indeed, one entire strand of duplex DNA is complementary to the opposing strand. During replication, the two strands unwindand each serves as a template for formation of new complementary strand, so that replication ends with two exact double-stranded copies.
Why is DNA called the Blueprint of Life?
Every cell in your body has the same "blueprint" or the same DNA. Like the blueprints of a house tell the builders how to construct a house, the DNA "blueprint" tells the cell how to build the organism. Yet, how can a heart be so different from a brain if all the cells contain the same instructions? Although much work remains in genetics, it has become apparent that a cell has the ability to turn off most genes and only work with the genes necessary to do a job. We also know that a lot of DNA apparently is nonsense and codes for nothing. These regions of DNA that do not code for proteins are called "introns", or sometimes "junk DNA". The sections of DNA that do actually code from proteins are called "exons".
Functional neuroimaging
Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions.
It is primarily used as a research tool in cognitive neuroscience and neuropsychology.
Common methods include positron emission tomography (PET), functional magnetic resonance imaging (fMRI), multichannel electroencephalography (EEG) or magnetoencephalography (MEG), and near infrared spectroscopic imaging (NIRSI).
PET, fMRI and NIRSI can measure localized changes in cerebral blood flow related to neural activity..
(http://www.sciencedaily.com/articles/f/functional_neuroimaging.htm)
It is primarily used as a research tool in cognitive neuroscience and neuropsychology.
Common methods include positron emission tomography (PET), functional magnetic resonance imaging (fMRI), multichannel electroencephalography (EEG) or magnetoencephalography (MEG), and near infrared spectroscopic imaging (NIRSI).
PET, fMRI and NIRSI can measure localized changes in cerebral blood flow related to neural activity..
(http://www.sciencedaily.com/articles/f/functional_neuroimaging.htm)
Functional neuroimaging
Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions.
It is primarily used as a research tool in cognitive neuroscience and neuropsychology.
Common methods include positron emission tomography (PET), functional magnetic resonance imaging (fMRI), multichannel electroencephalography (EEG) or magnetoencephalography (MEG), and near infrared spectroscopic imaging (NIRSI).
PET, fMRI and NIRSI can measure localized changes in cerebral blood flow related to neural activity..
(http://www.sciencedaily.com/articles/f/functional_neuroimaging.htm)
It is primarily used as a research tool in cognitive neuroscience and neuropsychology.
Common methods include positron emission tomography (PET), functional magnetic resonance imaging (fMRI), multichannel electroencephalography (EEG) or magnetoencephalography (MEG), and near infrared spectroscopic imaging (NIRSI).
PET, fMRI and NIRSI can measure localized changes in cerebral blood flow related to neural activity..
(http://www.sciencedaily.com/articles/f/functional_neuroimaging.htm)
Alpha wave
Alpha waves are electromagnetic oscillations in the frequency range of 8-12 Hz arising from synchronous and coherent (in phase / constructive) electrical activity of large groups of neurons in the human brain.
EEG Biofeedback Training (often called neurotherapy or neurofeedback) is a learning strategy that enables persons to alter their brain waves by getting a feedback of their present state..
Electroencephalography — Electroencephalography is the neurophysiologic measurement of the electrical activity of the brain by recording from electrodes placed on the scalp ...
EEG Biofeedback Training (often called neurotherapy or neurofeedback) is a learning strategy that enables persons to alter their brain waves by getting a feedback of their present state..
Electroencephalography — Electroencephalography is the neurophysiologic measurement of the electrical activity of the brain by recording from electrodes placed on the scalp ...
Progress Toward Artificial Tissue?
implants and the growth of artificial tissue and organs, it is important to generate materials with characteristics that closely emulate nature. However, the tissue in our bodies has a combination of traits that are very hard to recreate in synthetic materials: It is both soft and very tough.
A team of Australian and Korean researchers led by Geoffrey M. Spinks and Seon Jeong Kim has now developed a novel, highly porous, sponge-like material whose mechanical properties closely resemble those of biological soft tissues. It consists of a robust network of DNA strands and carbon nanotubes.
Soft tissues, such as tendons, muscles, arteries, and skin or other organs, obtain their mechanical support from the extracellular matrix, a network of protein-based nanofibers. Different protein morphologies in the extracellular matrix produce tissue with a wide range of stiffness. Implants and scaffolding for tissue growth require porous, soft materials -- which are usually very fragile. Because many biological tissues are regularly subjected to intense mechanical loads, it is also important that the implant material have comparable elasticity in order to avoid inflammation. At the same time, the material must be very strong and resilient, or it may give out.
The new concept uses DNA strands as a matrix; the strands completely “wrap” the scaffold-forming carbon nanotubes in the presence of an ionic liquid, networking them to form a gel. This gel can be spun: just as silk and synthetic fibers can be wet-spun for textiles, the gel can be made into very fine threads when injected into a special bath. The dried fibers have a porous, sponge-like structure and consist of a network of intertwined 50 nm-wide nanofibers. Soaking in a calcium chloride solution further cross-links the DNA, causing the fibers to become denser and more strongly connected.
These spongy fibers resemble the collagen fiber networks of the biological extracellular matrix. They can also be knotted, braided, or woven into textile-like structures. This results in materials that are as elastic as the softest natural tissues while simultaneously deriving great strength from the robust DNA links.
An additional advantage is the electrical conductivity of the new material, which can thus also be used in electrodes for mechanical actuators, energy storage, and sensors. For example, the researchers were able to produce a hydrogen peroxide sensor. The carbon nanotubes catalyze the oxidation of hydrogen peroxide, which results in a measurable current. Hydrogen peroxide plays a role in normal heart function and certain heart diseases. A robust sensor with elasticity similar to the heart muscle would be of great help in researching these relationships.
(http://www.sciencedaily.com/releases/2009/05/090515104227.htm)
A team of Australian and Korean researchers led by Geoffrey M. Spinks and Seon Jeong Kim has now developed a novel, highly porous, sponge-like material whose mechanical properties closely resemble those of biological soft tissues. It consists of a robust network of DNA strands and carbon nanotubes.
Soft tissues, such as tendons, muscles, arteries, and skin or other organs, obtain their mechanical support from the extracellular matrix, a network of protein-based nanofibers. Different protein morphologies in the extracellular matrix produce tissue with a wide range of stiffness. Implants and scaffolding for tissue growth require porous, soft materials -- which are usually very fragile. Because many biological tissues are regularly subjected to intense mechanical loads, it is also important that the implant material have comparable elasticity in order to avoid inflammation. At the same time, the material must be very strong and resilient, or it may give out.
The new concept uses DNA strands as a matrix; the strands completely “wrap” the scaffold-forming carbon nanotubes in the presence of an ionic liquid, networking them to form a gel. This gel can be spun: just as silk and synthetic fibers can be wet-spun for textiles, the gel can be made into very fine threads when injected into a special bath. The dried fibers have a porous, sponge-like structure and consist of a network of intertwined 50 nm-wide nanofibers. Soaking in a calcium chloride solution further cross-links the DNA, causing the fibers to become denser and more strongly connected.
These spongy fibers resemble the collagen fiber networks of the biological extracellular matrix. They can also be knotted, braided, or woven into textile-like structures. This results in materials that are as elastic as the softest natural tissues while simultaneously deriving great strength from the robust DNA links.
An additional advantage is the electrical conductivity of the new material, which can thus also be used in electrodes for mechanical actuators, energy storage, and sensors. For example, the researchers were able to produce a hydrogen peroxide sensor. The carbon nanotubes catalyze the oxidation of hydrogen peroxide, which results in a measurable current. Hydrogen peroxide plays a role in normal heart function and certain heart diseases. A robust sensor with elasticity similar to the heart muscle would be of great help in researching these relationships.
(http://www.sciencedaily.com/releases/2009/05/090515104227.htm)
Scientists Create Custom 3-dimensional Structures With 'DNA Origami'
art of origami with nanotechnology, Dana-Farber Cancer Institute researchers have folded sheets of DNA into multilayered objects with dimensions thousands of times smaller than the thickness of a human hair. These tiny structures could be forerunners of custom-made biomedical nanodevices such as "smart" delivery vehicles that would sneak drugs into patients' cells, where they would dump their cargo on a specific molecular target.
While creation of structures from single layers of DNA has been reported previously, William Shih, PhD, senior author of the study appearing in the May 21 issue of Nature, said the multi-layer process he and his colleagues developed should enable scientists to make customized DNA objects approximating almost any three-dimensional shape. Multilayered objects are more rigid and stable, thus better able to withstand the intracellular environment, which "is chaotic and violent, like being in a hurricane," Shih said. "We think this is a big advance."
Shih is a researcher in Dana-Farber's Cancer Biology program. He is also an assistant professor in the Department of Biological Chemistry and Molecular Pharmacology at Harvard Medical School, and a Core Faculty member of the Wyss Institute for Biologically Inspired Engineering at Harvard.
Masters of the ancient Japanese art of origami make a series of folds in a single piece of paper to form stunningly intricate models of animals and other shapes. "We focus on doing this with DNA," explained Shih. While DNA is best known as the stuff of which genes are made, here the scientists use long DNA molecules strictly as a building component, not a blueprint for making proteins. Shih and his colleagues reported in the Nature paper that they were able to construct a number of DNA objects, including a genie bottle, two kinds of crosses, a square nut, and a railed bridge.
DNA origami is an outgrowth of research in nanotechnology - using atoms and molecules as building blocks for new devices that can be deployed in medicine, electronics, and other fields. Scientists envision using the minuscule structures -- which are about the size of small viruses -- to mimic some of the "machines" within cells that carry out essential functions, like forming containers for molecular cargos and transporting them from one place to another.
"This is something that nature is very good at -- making many complex machines with great control. Nature optimizes cellular technology through millions of years of evolution; we don't have that much time, so we need to come up with other design approaches," Shih said.
DNA origami are built as a sheet of parallel double-helices, each consisting of two intertwined strands made up of units called nucleotides. Long strands of DNA serving as a "scaffold" are folded back and forth by short strands of DNA serving as "staples" that knit together segments of the scaffold. The DNA sheet, which Shih likens to the thin bamboo mat that sushi chefs use to prepare maki rolls with filling, is then programmed to curl on itself into a series of layers that are locked in place by staples that traverse multiple layers.
With the design in hand, the scientists then order the DNA staple strands from a company, which take about three days to be synthesized and shipped. Fabricating the desired structure involves mixing the DNA scaffold and staple strands, quickly heating the mixture, and then slowly cooling the sample. This process coaxes the DNA to "self-assemble" and make billions of copies of the desired object. The process takes about a week, though the researchers intend to improve this rate. Finally, the researchers can check the finished product using an electron microscope.
The tiny machines the researchers are aiming for could, for example, act as navigation aids to guide bubble-like sacs filled with medicines. "These machines could be placed on the outside of the drug-delivery vehicles to help them cross biological barriers, or help them outwit mechanisms that are trying to remove things from the bloodstream, so they can reach their target," suggested Shih.
The technology could also be useful in diagnostics of the future. While current lab tests can measure the concentration of different substances in the body, it may be possible with DNA "to measure the concentration of something within a single cell," said Shih.
In addition to Shih and Douglas, the authors of the Nature paper include Hendrik Dietz, PhD, Tim Liedl, PhD, Björn Högberg, PhD, and Franziska Graf, of Dana-Farber and Harvard Medical School.
The research was supported by grants from the National Institutes of Health, the Claudia Adams Barr Program, the Wyss Institute for Biologically Inspired Engineering at Harvard, and several fellowships.
(http://www.sciencedaily.com/releases/2009/05/090520140405.htm)
While creation of structures from single layers of DNA has been reported previously, William Shih, PhD, senior author of the study appearing in the May 21 issue of Nature, said the multi-layer process he and his colleagues developed should enable scientists to make customized DNA objects approximating almost any three-dimensional shape. Multilayered objects are more rigid and stable, thus better able to withstand the intracellular environment, which "is chaotic and violent, like being in a hurricane," Shih said. "We think this is a big advance."
Shih is a researcher in Dana-Farber's Cancer Biology program. He is also an assistant professor in the Department of Biological Chemistry and Molecular Pharmacology at Harvard Medical School, and a Core Faculty member of the Wyss Institute for Biologically Inspired Engineering at Harvard.
Masters of the ancient Japanese art of origami make a series of folds in a single piece of paper to form stunningly intricate models of animals and other shapes. "We focus on doing this with DNA," explained Shih. While DNA is best known as the stuff of which genes are made, here the scientists use long DNA molecules strictly as a building component, not a blueprint for making proteins. Shih and his colleagues reported in the Nature paper that they were able to construct a number of DNA objects, including a genie bottle, two kinds of crosses, a square nut, and a railed bridge.
DNA origami is an outgrowth of research in nanotechnology - using atoms and molecules as building blocks for new devices that can be deployed in medicine, electronics, and other fields. Scientists envision using the minuscule structures -- which are about the size of small viruses -- to mimic some of the "machines" within cells that carry out essential functions, like forming containers for molecular cargos and transporting them from one place to another.
"This is something that nature is very good at -- making many complex machines with great control. Nature optimizes cellular technology through millions of years of evolution; we don't have that much time, so we need to come up with other design approaches," Shih said.
DNA origami are built as a sheet of parallel double-helices, each consisting of two intertwined strands made up of units called nucleotides. Long strands of DNA serving as a "scaffold" are folded back and forth by short strands of DNA serving as "staples" that knit together segments of the scaffold. The DNA sheet, which Shih likens to the thin bamboo mat that sushi chefs use to prepare maki rolls with filling, is then programmed to curl on itself into a series of layers that are locked in place by staples that traverse multiple layers.
With the design in hand, the scientists then order the DNA staple strands from a company, which take about three days to be synthesized and shipped. Fabricating the desired structure involves mixing the DNA scaffold and staple strands, quickly heating the mixture, and then slowly cooling the sample. This process coaxes the DNA to "self-assemble" and make billions of copies of the desired object. The process takes about a week, though the researchers intend to improve this rate. Finally, the researchers can check the finished product using an electron microscope.
The tiny machines the researchers are aiming for could, for example, act as navigation aids to guide bubble-like sacs filled with medicines. "These machines could be placed on the outside of the drug-delivery vehicles to help them cross biological barriers, or help them outwit mechanisms that are trying to remove things from the bloodstream, so they can reach their target," suggested Shih.
The technology could also be useful in diagnostics of the future. While current lab tests can measure the concentration of different substances in the body, it may be possible with DNA "to measure the concentration of something within a single cell," said Shih.
In addition to Shih and Douglas, the authors of the Nature paper include Hendrik Dietz, PhD, Tim Liedl, PhD, Björn Högberg, PhD, and Franziska Graf, of Dana-Farber and Harvard Medical School.
The research was supported by grants from the National Institutes of Health, the Claudia Adams Barr Program, the Wyss Institute for Biologically Inspired Engineering at Harvard, and several fellowships.
(http://www.sciencedaily.com/releases/2009/05/090520140405.htm)
Somatic cell nuclear transfer
n genetics and developmental biology, somatic cell nuclear transfer (SCNT) is a laboratory technique for creating an ovum with a donor nucleus.
It can be used in embryonic stem cell research, or in regenerative medicine where it is sometimes referred to as "therapeutic cloning." It can also be used as the first step in the process of reproductive cloning.
In SCNT the nucleus, which contains the organism's DNA, of a somatic cell (a body cell other than a sperm or egg cell) is removed and the rest of the cell discarded.
At the same time, the nucleus of an egg cell is removed.
The nucleus of the somatic cell is then inserted into the enucleated egg cell.
After being inserted into the egg, the somatic cell nucleus is reprogrammed by the host cell.
The egg, now containing the nucleus of a somatic cell, is stimulated with a shock and will begin to divide.
After many mitotic divisions in culture, this single cell forms a blastocyst (an early stage embryo with about 100 cells) with almost identical DNA to the original organism..
It can be used in embryonic stem cell research, or in regenerative medicine where it is sometimes referred to as "therapeutic cloning." It can also be used as the first step in the process of reproductive cloning.
In SCNT the nucleus, which contains the organism's DNA, of a somatic cell (a body cell other than a sperm or egg cell) is removed and the rest of the cell discarded.
At the same time, the nucleus of an egg cell is removed.
The nucleus of the somatic cell is then inserted into the enucleated egg cell.
After being inserted into the egg, the somatic cell nucleus is reprogrammed by the host cell.
The egg, now containing the nucleus of a somatic cell, is stimulated with a shock and will begin to divide.
After many mitotic divisions in culture, this single cell forms a blastocyst (an early stage embryo with about 100 cells) with almost identical DNA to the original organism..
Gene therapy
Gene therapy is the insertion of genes into an individual's cells and tissues to treat a disease, and hereditary diseases in which a defective mutant allele is replaced with a functional one.
Although the technology is still in its infancy, it has been used with some success.
Antisense therapy is not strictly a form of gene therapy, but is a genetically-mediated therapy and is often considered together with other methods.
In most gene therapy studies, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene.
A carrier called a vector must be used to deliver the therapeutic gene to the patient's target cells.
Currently, the most common type of vectors are viruses that have 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 harness this ability by manipulating the viral genome to remove disease-causing genes and insert therapeutic ones. Target cells such as the patient's liver or lung cells are infected with the 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. In theory it is possible to transform either somatic cells (most cells of the body) or cells of the germline (such as sperm cells, ova, and their stem cell precursors).
All gene therapy to date on humans has been directed at somatic cells, whereas germline engineering in humans remains controversial.
For the introduced gene to be transmitted normally to offspring, it needs not only to be inserted into the cell, but also to be incorporated into the chromosomes by genetic recombination. Somatic gene therapy can be broadly split in to two categories: ex vivo, which means exterior (where cells are modified outside the body and then transplanted back in again) and in vivo, which means interior (where genes are changed in cells still in the body).
Recombination-based approaches in vivo are especially uncommon, because for most DNA constructs recombination has a very low probability..
Although the technology is still in its infancy, it has been used with some success.
Antisense therapy is not strictly a form of gene therapy, but is a genetically-mediated therapy and is often considered together with other methods.
In most gene therapy studies, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene.
A carrier called a vector must be used to deliver the therapeutic gene to the patient's target cells.
Currently, the most common type of vectors are viruses that have 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 harness this ability by manipulating the viral genome to remove disease-causing genes and insert therapeutic ones. Target cells such as the patient's liver or lung cells are infected with the 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. In theory it is possible to transform either somatic cells (most cells of the body) or cells of the germline (such as sperm cells, ova, and their stem cell precursors).
All gene therapy to date on humans has been directed at somatic cells, whereas germline engineering in humans remains controversial.
For the introduced gene to be transmitted normally to offspring, it needs not only to be inserted into the cell, but also to be incorporated into the chromosomes by genetic recombination. Somatic gene therapy can be broadly split in to two categories: ex vivo, which means exterior (where cells are modified outside the body and then transplanted back in again) and in vivo, which means interior (where genes are changed in cells still in the body).
Recombination-based approaches in vivo are especially uncommon, because for most DNA constructs recombination has a very low probability..
Blood Vessels
Knowledge of the structure and function of blood vessels and other aspects of the heart and vascular system are essential parts of training in many therapies, such as Massage (in its many forms, "Indian Head Massage", "Swedish Massage", "Accupressure Massage" etc.), Aromatherapy, Acupuncture, Shiatsu, and others. This page is intended to include the detail required for most Basic / First Level Courses in these therapies, and some ITEC Diplomas.
The main types of blood vessels are: Arteries, Arterioles, Capillaries, Venules, Veins.
The main types of blood vessels are: Arteries, Arterioles, Capillaries, Venules, Veins.
Electrocardiography.
An electrocardiogram is a test that measures the electrical activity of the heart. This includes the rate and regularity of beats as well as the size and position of the chambers, any damage to the heart, and effects of drugs or devices to regulate the heart.
HODGIN DISEASE AND LONG TERM CARDIOVASCULAR RISK
NEW YORK (Reuters Health) May 14 - Hodgkin lymphoma survivors are at high risk for cardiovascular disease, a Swedish study confirms. The risk is particularly high for patients treated for Hodgkin lymphoma before the age of 40 years and with a family history of heart disease.
In the April 15 issue of the International Journal of Cancer, the study team notes that "previous studies have shown increased cardiovascular mortality as late side effects of Hodgkin lymphoma patients." The aim of the current study, Dr. Anne Andersson of Umea University and colleagues explain, was to identify "stratifying risk factors for surveillance."
The investigators used the Swedish Cancer Registry to identify 6946 patients diagnosed with Hodgkin lymphoma between 1965 and 1995 and the Swedish Multigenerational Registry to identify a total of 17,858 first-degree relatives of the patients.
Among 4,635 Hodgkin lymphoma patients who survived one year or longer after diagnosis, 1,413 episodes of inpatient care for coronary artery disease, congestive heart failure, stroke and/or valvular disease in 698 individuals were recorded in the Swedish Hospital Discharge Registry.
Average follow up was 11.8 years and, according to the investigators, the standard incidence ratio (SIR) for cardiovascular disease was "increasing at the time of follow-up and the risk was higher for those treated for Hodgkin lymphoma before the age of 40."
The SIR for cardiovascular disease 10 to 19 years after Hodgkin lymphoma treatment was 3.06 for all Hodgkin lymphoma patients, and 5.53 in patients with a positive family history for cardiovascular disease.
For Hodgkin lymphoma survivors treated before age 40, the SIR for congestive heart failure 10 to 19 years after treatment was 3.45; it was 6.67 for those with a positive family history of cardiovascular disease, the report states.
For Hodgkin lymphoma survivors treated before the age 40 and followed for 20 years or longer, there was a 10-fold increase in risk for congestive heart failure. For this group, a positive family history of congestive heart failure yielded a SIR of 25.00.
Dr. Andersson and colleagues conclude, "A family history of cardiovascular disease could be particularly important for identifying patients at risk for early coronary artery disease and congestive heart failure."
The study, they add, "implicates in concert with two other large cohorts the need for cardiovascular intervention in this high risk group."
In the April 15 issue of the International Journal of Cancer, the study team notes that "previous studies have shown increased cardiovascular mortality as late side effects of Hodgkin lymphoma patients." The aim of the current study, Dr. Anne Andersson of Umea University and colleagues explain, was to identify "stratifying risk factors for surveillance."
The investigators used the Swedish Cancer Registry to identify 6946 patients diagnosed with Hodgkin lymphoma between 1965 and 1995 and the Swedish Multigenerational Registry to identify a total of 17,858 first-degree relatives of the patients.
Among 4,635 Hodgkin lymphoma patients who survived one year or longer after diagnosis, 1,413 episodes of inpatient care for coronary artery disease, congestive heart failure, stroke and/or valvular disease in 698 individuals were recorded in the Swedish Hospital Discharge Registry.
Average follow up was 11.8 years and, according to the investigators, the standard incidence ratio (SIR) for cardiovascular disease was "increasing at the time of follow-up and the risk was higher for those treated for Hodgkin lymphoma before the age of 40."
The SIR for cardiovascular disease 10 to 19 years after Hodgkin lymphoma treatment was 3.06 for all Hodgkin lymphoma patients, and 5.53 in patients with a positive family history for cardiovascular disease.
For Hodgkin lymphoma survivors treated before age 40, the SIR for congestive heart failure 10 to 19 years after treatment was 3.45; it was 6.67 for those with a positive family history of cardiovascular disease, the report states.
For Hodgkin lymphoma survivors treated before the age 40 and followed for 20 years or longer, there was a 10-fold increase in risk for congestive heart failure. For this group, a positive family history of congestive heart failure yielded a SIR of 25.00.
Dr. Andersson and colleagues conclude, "A family history of cardiovascular disease could be particularly important for identifying patients at risk for early coronary artery disease and congestive heart failure."
The study, they add, "implicates in concert with two other large cohorts the need for cardiovascular intervention in this high risk group."
DNA Repairing
DNA Repairing
When it was discovered that DNA is the macromolecular carrier of essentially all genetic information, it was assumed that DNA is extremely stable. Consequently, it came as something of a surprise to learn that DNA is actually unstable and subject to continual damage. When DNA damage is severe, the cell is unable toreplicate and may die. Repair of DNA must be regarded as essential for the preservation and transmission of genetic information in all life forms. In this article, we will discuss various types of DNA damage and the DNA repair systems that have evolved to correct that damage... However it can be rectified by some Methods.
DNA
DNA
A nucleic acid that carries the genetic information in the cell and is capable of self-replication and synthesis of RNA. DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. The sequence of nucleotides determines individual hereditary characteristics. This is known ad DNA..
Messenger RNA
Messenger RNA
The form of RNA that mediates the transfer of genetic information from the cell nucleus to ribosomes in the cytoplasm, where it serves as a template for protein synthesis. It is synthesized from a DNA template during the process of transcription. Such is called as mRNA..
RNA
RNA
Note on RNA is ...A polymeric constituent of all living cells and many viruses, consisting of a long, usually single-stranded chain of alternating phosphate and ribose units with the bases adenine, guanine, cytosine, and uracil bonded to the ribose. The structure and base sequence of RNA are determinants of protein synthesis and the transmission of genetic information.
Basics of Cloning
Have you ever wished you could have a clone of yourself to do homework while you hit the skate park or went out with your friends?
Cloning
Cloning is the creation of an organism that is an exact genetic copy of another. This means that every single bit of DNA is the same between the two!
You might not believe it, but there are human clones among us right now. They weren't made in a lab, though: they're identical twins, created naturally. Below, we'll see how natural identical twins relate to modern cloning technologies.
How is cloning done?
You may have first heard of cloning when Dolly the Sheep showed up on the scene in 1997. Cloning technologies have been around for much longer than Dolly, though.
How does one go about making an exact genetic copy of an organism? There are a couple of ways to do this: artificial embryo twinning and somatic cell nuclear transfer. How do these processes differ?
Artificial embryo twinning is the relatively low-tech version of cloning. As the name suggests, this technology mimics the natural process of creating identical twins.
Somatic cell nuclear transfer, (SCNT) uses a different approach than artificial embryo twinning, but it produces the same result: an exact clone, or genetic copy, of an individual. This was the method used to create Dolly the Sheep. Moving an object from one place to another.
To make Dolly, researchers isolated a somatic cell from an adult female sheep. Next, they transferred the nucleus from that cell to an egg cell from which the nucleus had been removed. After a couple of chemical tweaks, the egg cell, with its new nucleus, was behaving just like a freshly fertilized zygote. It developed into an embryo, which was implanted into a surrogate mother and carried to term.
learn.genetics.utah.edu
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