Tag Archives: Innate immune system

Immunisation

Products from Amazon.com

Definition:
Immunization, or immunisation, is the process by which an individual’s immune system becomes fortified against an agent (known as the immunogen).It  is the process whereby a person is made immune or resistant to an infectious disease.

CLICK & SEE

Immunization is done through various techniques, most commonly vaccination. Vaccines against microorganisms that cause diseases can prepare the body’s immune system, thus helping to fight or prevent an infection. The fact that mutations can cause cancer cells to produce proteins or other molecules that are known to the body forms the theoretical basis for therapeutic cancer vaccines. Other molecules can be used for immunization as well, for example in experimental vaccines against nicotine (NicVAX) or the hormone ghrelin in experiments to create an obesity vaccine.

Before the introduction of vaccines, the only way people became immune to an infectious disease was by actually getting the disease and surviving it. Smallpox (variola) was prevented in this way by inoculation, which produced a milder effect than the natural disease. It was introduced into England from Turkey by Lady Mary Wortley Montagu in 1721 and used by Zabdiel Boylston in Boston the same year. In 1798 Edward Jenner introduced inoculation with cowpox (smallpox vaccine), a much safer procedure. This procedure, referred to as vaccination, gradually replaced smallpox inoculation, now called variolation to distinguish it from vaccination. Until the 1880s vaccine/vaccination referred only to smallpox, but Louis Pasteur developed immunisation methods for chicken cholera and anthrax in animals and for human rabies, and suggested that the terms vaccine/vaccination should be extended to cover the new procedures. This can cause confusion if care is not taken to specify which vaccine is used e.g. measles vaccine or influenza vaccine.

When this system is exposed to molecules that are foreign to the body, called non-self, it will orchestrate an immune response, and it will also develop the ability to quickly respond to a subsequent encounter because of immunological memory. This is a function of the adaptive immune system. Therefore, by exposing an animal to an immunogen in a controlled way, its body can learn to protect itself: this is called active immunization.

The most important elements of the immune system that are improved by immunization are the T cells, B cells, and the antibodies B cells produce. Memory B cells and memory T cells are responsible for a swift response to a second encounter with a foreign molecule. Passive immunization is direct introduction of these elements into the body, instead of production of these elements by the body itself.

The most important elements of the immune system that are improved by immunization are the T cells, B cells, and the antibodies B cells produce. Memory B cells and memory T cells are responsible for a swift response to a second encounter with a foreign molecule. Passive immunization is direct introduction of these elements into the body, instead of production of these elements by the body itself.

Immunization is a proven tool for controlling and eliminating life-threatening infectious diseases and is estimated to avert between 2 and 3 million deaths each year. It is one of the most cost-effective health investments, with proven strategies that make it accessible to even the most hard-to-reach and vulnerable populations. It has clearly defined target groups; it can be delivered effectively through outreach activities; and vaccination does not require any major lifestyle change.

Immunizations are definitely less risky and an easier way to become immune to a particular disease than risking a milder form of the disease itself. They are important for both adults and children in that they can protect us from the many diseases out there. Through the use of immunizations, some infections and diseases have almost completely been eradicated throughout the United States and the World. One example is polio. Thanks to dedicated health care professionals and the parents of children who vaccinated on schedule, polio has been eliminated in the U.S. since 1979. Polio is still found in other parts of the world so certain people could still be at risk of getting it. This includes those people who have never had the vaccine, those who didn’t receive all doses of the vaccine, or those traveling to areas of the world where polio is still prevalent.

The Immunization can be achieved in an active or passive manner:
Vaccination is an active form of immunization.

Active immunization/vaccination has been named one of the “Ten Great Public Health Achievements in the 20th Century”.

Active immunization:.click & see
Active immunization can occur naturally when a person comes in contact with, for example, a microbe. The immune system will eventually create antibodies and other defenses against the microbe. The next time, the immune response against this microbe can be very efficient; this is the case in many of the childhood infections that a person only contracts once, but then is immune.

Artificial active immunization is where the microbe, or parts of it, are injected into the person before they are able to take it in naturally. If whole microbes are used, they are pre-treated.

The importance of immunization is so great that the American Centers for Disease Control and Prevention has named it one of the “Ten Great Public Health Achievements in the 20th Century”.  Live attenuated vaccines have decreased pathogenicity. Their effectiveness depends on the immune systems ability to replicate and elicits a response similar to natural infection. It is usually effective with a single dose. Examples of live, attenuated vaccines include measles, mumps, rubella, MMR, yellow fever, varicella, rotavirus, and influenza (LAIV).

Passive immunization:……...click & see
Passive immunization is where pre-synthesized elements of the immune system are transferred to a person so that the body does not need to produce these elements itself. Currently, antibodies can be used for passive immunization. This method of immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and if there are no B cells to produce more antibodies, they will disappear.

Passive immunization occurs physiologically, when antibodies are transferred from mother to fetus during pregnancy, to protect the fetus before and shortly after birth.

Artificial passive immunization is normally administered by injection and is used if there has been a recent outbreak of a particular disease or as an emergency treatment for toxicity, as in for tetanus. The antibodies can be produced in animals, called “serum therapy,” although there is a high chance of anaphylactic shock because of immunity against animal serum itself. Thus, humanized antibodies produced in vitro by cell culture are used instead if available.

Resources:
http://en.wikipedia.org/wiki/Immunization
http://www.who.int/topics/immunization/en/

Advertisements

Foe Turns Friend

A-beta, a protein implicated in Alzheimer’s, may be the brain’s shield against germs.
………………...CLICK & SEE THE PICTURES
For years, a prevailing theory has been that one of the chief villains in Alzheimer’s disease has no real function other than as a waste product that the brain never properly disposed of.

The material, a protein called beta amyloid, or A-beta, piles up into tough plaques that destroy signals between nerves. When that happens, people lose their memory, their personality changes and they stop recognising friends and family.

But now researchers at Harvard suggest that the protein has a real and unexpected function — it may be part of the brain’s normal defences against invading bacteria and other microbes.

Other Alzheimer’s researchers say the findings, reported in the current issue of the journal PLoS One, are intriguing.

The new hypothesis got its start late one Friday evening in the summer of 2007 in a laboratory at Harvard Medical School. The lead researcher, Rudolph Tanzi, a neurology professor who is also director of the genetics and aging unit at Massachusetts General Hospital, said he had been looking at a list of genes that seemed to be associated with Alzheimer’s disease.

To his surprise, many looked just like genes associated with the so-called innate immune system, a set of proteins the body uses to fight infections. The system is particularly important in the brain, because antibodies cannot get through the blood-brain barrier, the membrane that protects the brain. When the brain is infected, it relies on the innate immune system to protect it.

That evening, Tanzi wandered into the office of a junior faculty member, Robert Moir, and mentioned what he had seen. As Tanzi recalled, Moir turned to him and said, “Yeah, well, look at this.”

He handed Tanzi a spreadsheet. It was a comparison of A-beta and a well-known protein of the innate immune system, LL-37. The likenesses were uncanny. Among other things, the two proteins had similar structures. And like A-beta, LL-37 tends to clump into hard little balls.

In rodents, the protein that corresponds to LL-37 protects against brain infections. People who make low levels of LL-37 are at increased risk of serious infections and have higher levels of atherosclerotic plaques, arterial growths that impede blood flow.

The scientists could hardly wait to see if A-beta, like LL-37, killed microbes. They mixed A-beta with microbes that LL-37 is known to kill — listeria, staphylococcus, pseudomonas. It killed eight out of 12. “We did the assays exactly as they have been done for years,” Tanzi said. “And A-beta was as potent or, in some cases, more potent than LL-37.”

Then the investigators exposed the yeast Candida albicans, a major cause of meningitis, to tissue from the hippocampal regions of brains from people who had died of Alzheimer’s and from people of the same age who did not have dementia when they died.

Brain samples from Alzheimer’s patients were 24 per cent more active in killing the bacteria. But if the samples were first treated with an antibody that blocked A-beta, they were no better than brain tissue from non-demented people in killing the yeast.

The innate immune system is also set in motion by traumatic brain injuries and strokes and by atherosclerosis that causes reduced blood flow to the brain, Tanzi noted.

And the system is spurred by inflammation. It’s known that patients with Alzheimer’s have inflamed brains, but it hasn’t been clear whether A-beta accumulation was a cause or an effect of the inflammation. Perhaps, Tanzi said, A-beta levels rise as a result of the innate immune system’s response to inflammation; it may be a way the brain responds to a perceived infection. But does that mean Alzheimer’s disease is caused by an overly exuberant brain response to an infection?

That’s one possible reason, along with responses to injuries and inflammation and the effects of genes that cause A-beta levels to be higher than normal, Tanzi said. However, some researchers say that all the pieces of the A-beta innate immune systems hypothesis are not in place.

Dr Norman Relkin, director of the memory disorders programme at New York-Presbyterian / Weill Cornell hospital, said that although the idea was “unquestionably fascinating”, the evidence for it was “a bit tenuous”.

As for the link with infections, Dr Steven DeKosky, an Alzheimer’s researcher at the Virginia School of Medicine, noted that scientists have long looked for evidence linking infections to Alzheimer’s and have come up mostly empty handed.

But if Tanzi is correct about A-beta being part of the innate immune system, that would raise questions about the search for treatments to eliminate the protein from the brain.

“It means you don’t want to hit A-beta with a sledgehammer,” Tanzi said.

But other scientists not connected with the discovery said they were impressed by the new findings. “It changes our thinking about Alzheimer’s disease,” said Dr Eliezer Masliah, who heads the experimental neuropathology laboratory at the University of California, San Diego.

Source : New York Times News Service

Reblog this post [with Zemanta]

Corn

What are corns?
Corns are annoying and sometimes painful thickenings that form in the skin in areas that are being pressed on by underlying bones. They occur on parts of the feet and sometimes the fingers. Corns can be painful to walk on even when they are small. Common locations are:

* On the sole, over the metatarsal arch (the “ball” of the foot);

* On the outside of the fifth (pinky) toe, where it rubs against the shoe; and

* Between the 4th and 5th toes. Unlike other corns which are firm and flesh-colored, corns between the toes are often whitish and messy; they are sometimes called “soft corns.”

It’s usually hard to know where finger corns come from since they often don’t appear at sites of obvious pressure.

click & see

How can corns be prevented?
Generally speaking, corns are a disease of civilization. If we didn’t wear shoes, we wouldn’t have them. Potential preventive measures therefore include:

1. Moving to Tahiti to stroll on the sand in your bare tootsies! This is a pleasant approach, as long as you never have to go back home and walk in shoes again.
2. For the incurably civilized, wearing comfortable shoes is useful. The idea is to avoid having footgear press on the outside of the 5th toe, or pressing the 4th and 5th toes together.
3. Another approach is to pad the potentially affected area. You can buy many sorts of padding at the drugstore:

* Cushions to put between the toes;
* Foam or moleskin pads to put over the places where corns form;
* Foam pads with holes in the center (like doughnuts or bagels), which redistribute pressure around the corn instead of right over it; and
* Cushioned insoles to pad your feet and alleviate mechanical pressure.

How can corns be treated?
You can buy many types of medicated products to chemically pare down the thickened, dead skin overlying the corn. These products are share the same active ingredient –salicylic acid.

Salicylic acid is a keratolytic, which means it dissolves the protein (keratin) that makes up most of both your corn and the thick layer of dead skin which often tops it. Used once a day as indicated on the package directions, these products are gentle and safe. Salicylic acid treatments are available in different forms including:

* Applicators
* Drops
* Pads
* Plasters

All of these treatment will turn the top of the skin white and allow you to trim or peel away dead tissue, making the corn protrude and hurt less.

It generally is recommended that salicylic acid not be used in diabetics or when there is poor circulation (because of concern about how normally the skin can heal); however, in practice, salicylic acid is withheld only when there are clear signs of ongoing inflammation of the skin.

When should you seek professional treatment for corns?
If the corn bothers you and doesn’t respond to salicylic acid and trimming, you might consider seeing a physician or podiatrist who can physically pare corns with scalpels. (It’s better not to do this yourself, especially if you’re elderly or diabetic.) Podiatrists also can measure and fit you with orthotic devices to redistribute your weight on your feet while you walk so that pressure from the foot bones doesn’t focus on your corns. (Off-the-shelf cushioned insoles are one-size-fits-all and may not be effective.)

Surgery for corns is rarely necessary. There is never a point to cutting out a corn. The pressure that caused it to form in the first place will just make it come back. When necessary, surgery for corns involves shaving the underlying bone that is pressing on the skin to reduce the pressure.

This link may show some natural remedy for corns.

Source:www.medicinenet.com