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Showing posts from January, 2013

Magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body. In many cases MRI gives different information about structures in the body than can be seen with an X-ray, ultrasound, or computed tomography (CT) scan. MRI also may show problems that cannot be seen with other imaging methods. For an MRI test, the area of the body being studied is placed inside a special machine that contains a strong magnet. Pictures from an MRI scan are digital images that can be saved and stored on a computer for more study. The images also can be reviewed remotely, such as in a clinic or an operating room. In some cases, contrast material may be used during the MRI scan to show certain structures more clearly. See pictures of a standard MRI machine and an open MRI machine . Why It Is Done Magnetic resonance imaging (MRI) is done for many reasons. It is used to find problems such as tumors, bleeding, inj

What is Computed Tomography?

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Conventional X ray Images All x-ray imaging is based on the absorption of x rays as they pass through the different parts of a patient's body. Depending on the amount absorbed in a particular tissue such as muscle or lung, a different amount of x rays will pass through and exit the body. The amount of x rays absorbed contributes to the  radiation dose  to the patient. During conventional x-ray imaging, the exiting x rays interact with a detection device (x-ray film or other image receptor) and provide a 2-dimensional projection image of the tissues within the patient's body - an x-ray produced "photograph" called a "radiograph." The chest x ray (Figure 1) is the most common medical imaging examination. During this examination, an image of the heart, lungs, and other anatomy is recorded on the film. Figure 1: Chest X ray Image Computed Tomography (CT) Although also based on the variable absorption of x rays by different tissues, computed tomograp

Drug Side Effects

Information about Drug Side Effects A  side effect  is usually regarded as an undesirable secondary effect which occurs in addition to the desired therapeutic effect of a drug or medication. Side effects may vary for each individual depending on the person's disease state, age, weight, gender, ethnicity and general health. Side effects can occur when commencing, decreasing/increasing dosages, or ending a drug or medication regimen. Side effects may also lead to non-compliance with prescribed treatment. When side effects of a drug or medication are severe, the dosage may be adjusted or a second medication may be prescribed. Lifestyle or dietary changes may also help to minimize side effects.

Glutamate as a Neurotransmitter

Glutamate Outside the community of biomedical scientists, glutamate is probably best known as "monosodium glutamate" or "MSG" which is used as a flavor or taste enhancer in food. It is usually available together with other food additives and spices in most large food stores. Some people may also have heard the term "Chinese restaurant syndrome" which is a sudden fall in blood pressure with subsequent fainting after ingestion of very spicy food. Excessive use of MSG has been suggested to be the cause, but this is controversial. The use of glutamate as a food additive, however, is not the reason for the enormous scientific interest in glutamate. Glutamate is the major excitatory transmitter in the brain The main motivation for the ongoing World Wide research on glutamate is due to the role of glutamate in the signal transduction in the nervous systems of apparently all complex living organisms, including man. Glutamate is considered to be the major mediato

What are the risk factors for breast cancer?

What are the risk factors for breast cancer? A risk factor is anything that affects your chance of getting a disease, such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, mouth, larynx (voice box), bladder, kidney, and several other organs. But risk factors don't tell us everything. Having a risk factor, or even several, does not mean that you will get the disease. Most women who have one or more breast cancer risk factors never develop the disease, while many women with breast cancer have no apparent risk factors (other than being a woman and growing older). Even when a woman with risk factors develops breast cancer, it is hard to know just how much these factors might have contributed. There are different kinds of risk factors. Some factors, like a person's age or race, can't be changed. Others are linked to cancer-causing f

Cell line

(Science: cell culture) a cell line is a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. lines differ from cell strains in that they have escaped the Hayflick limit and become immortalised. Some species, particularly rodents, give rise to lines relatively easily, whereas other species do not. No cell lines have been produced from avian tissues and the establishment of cell lines from human tissue is difficult. Many cell biologists would consider that a cell line is by definition already abnormal and that it is on the way towards becoming the culture equivalent of a neoplastic cell.

Cell line

(Science: cell culture) a cell line is a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. lines differ from cell strains in that they have escaped the Hayflick limit and become immortalised. Some species, particularly rodents, give rise to lines relatively easily, whereas other species do not. No cell lines have been produced from avian tissues and the establishment of cell lines from human tissue is difficult. Many cell biologists would consider that a cell line is by definition already abnormal and that it is on the way towards becoming the culture equivalent of a neoplastic cell.

Cell line

(Science: cell culture) a cell line is a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. lines differ from cell strains in that they have escaped the Hayflick limit and become immortalised. Some species, particularly rodents, give rise to lines relatively easily, whereas other species do not. No cell lines have been produced from avian tissues and the establishment of cell lines from human tissue is difficult. Many cell biologists would consider that a cell line is by definition already abnormal and that it is on the way towards becoming the culture equivalent of a neoplastic cell.

polymorphism

Generally, the ability to appear in many forms. In  object-oriented programming ,  polymorphism  refers to a  programming language's  ability to process objects differently depending on their  data type  or  class . More specifically, it is the ability to redefine  methods  for  derived classes.  For example, given a base class  shape,  polymorphism enables the programmer to define different  area  methods for any number of derived classes, such as circles, rectangles and triangles. No matter what shape an object is, applying the  area  method to it will return the correct results. Polymorphism is considered to be a requirement of any true object-oriented programming language (OOPL).

What is Gene Expression?

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Gene  expression  is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding  genes  such as rRNA genes or tRNA genes, the product is a functional RNA . The process of gene expression is used by all known life - eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea) and  viruses  - to generate the macromolecular machinery for life. Gene structure and  gene  expression in higher organisms Several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for cellular differentiation, morphogenesis and the versatility and adaptability of any organism. Gene regulation may also serve as a substrate for evolutionary change, since control of the timing, location, and

What Is Serotonin? What Does Serotonin Do?

Serotonin, also known as  5-hydroxytryptamine  is a hormone in the pineal gland, the digestive tract, the central nervous system, and blood platelets. A hormone is a substance our body produces that regulates and controls the activity of certain cells or organs. The molecular formula of serotonin is C 10 H 12 N 2 O. Serotonin is a neurotransmitter - this is a chemical substance that transmits nerve impulses across the space between nerve cells or neurons. We call these spaces synapses. Serotonin plays an important part in the regulation of learning, mood, sleep and vasoconstriction (constriction of blood vessels). Experts say serotonin also might have a role in  anxiety ,  migraine , vomiting and appetite. Alterations in serotonin levels in the brain may affect mood. Some  antidepressant  medications affect the action of serotonin, i.e. they are used to treat  depression . About 80% of our body's total serotonin is in the gut, in the enterochromaffin cells - where it regulates int