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…”KNOW HOW VACCINES ARE MADE BEFORE YOU MISTRUST THEM”…MAKING VACCINES: HOW ARE VACCINES MADE? Several basic strategies ...
03/05/2021

…”KNOW HOW VACCINES ARE MADE BEFORE YOU MISTRUST THEM”…
MAKING VACCINES: HOW ARE VACCINES MADE?
Several basic strategies are used to make vaccines. The strengths and limitations of each approach are described here.
1)- WEAKEN THE VIRUS:
Using this strategy, viruses are weakened so they reproduce very poorly once inside the body. The vaccines for measles, mumps, German measles (rubella), rotavirus, oral polio (not used in the U.S.), chickenpox (varicella), and influenza (intranasal version) vaccines are made this way. Viruses usually cause disease by reproducing themselves many times in the body. Whereas natural viruses reproduce thousands of times during an infection, vaccine viruses usually reproduce fewer than 20 times. Because vaccine viruses don't reproduce very much, they don't cause disease, but vaccine viruses replicate well enough to induce "memory B cells" that protect against infection in the future. Find out more about these and other cells of the immune system.

The advantage of live, "weakened" vaccines is that one or two doses provide immunity that is usually life-long. The limitation of this approach is that these vaccines usually cannot be given to people with weakened immune systems (like people with cancer or AIDS). Find out more about what happens when the immune system doesn’t work properly.
Watch this video to see how viruses are weakened to make vaccines.
2)- INACTIVATE THE VIRUS:
Using this strategy, viruses are completely inactivated (or killed) with a chemical. By killing the virus, it cannot possibly reproduce itself or cause disease. The inactivated polio, hepatitis A, influenza (shot), and rabies vaccines are made this way. Because the virus is still "seen" by the body, cells of the immune system that protect against disease are generated.
THERE ARE TWO BENEFITS TO THIS APPROACH:
• The vaccine cannot cause even a mild form of the disease that it prevents
• The vaccine can be given to people with weakened immune systems
However, the limitation of this approach is that it typically requires several doses to achieve immunity.
3)- USE PART OF THE VIRUS:
Using this strategy, just one part of the virus is removed and used as a vaccine. The hepatitis B, shingles, human papillomavirus (HPV), and one of the influenza vaccines are made this way. The vaccine is composed of a protein that resides on the surface of the virus. This strategy can be used when an immune response to one part of the virus (or bacteria) is responsible for protection against disease.

These vaccines can be given to people with weakened immunity and appear to induce long-lived immunity after two doses.
Watch this video to see how genetic engineering is used to make effective vaccines.
4)- USE PART OF THE BACTERIA:
Some bacteria cause disease by making a harmful protein called a toxin. Several vaccines are made by taking toxins and inactivating them with a chemical (the toxin, once inactivated, is called a toxoid). By inactivating the toxin, it no longer causes disease. The diphtheria, teta**s and pertussis vaccines are made this way.

Another strategy to make a bacterial vaccine is to use part of the sugar coating (or polysaccharide) of the bacteria. Protection against infection by certain bacteria is based on immunity to this sugar coating (and not the whole bacteria). However, because young children don't make a very good immune response to the sugar coating alone, the coating is linked to a harmless protein (this is called a "conjugated polysaccharide" vaccine). The Haemophilus influenzae type B (or Hib), pneumococcal, and some meningococcal vaccines are made this way.
Two meningococcal vaccines, which prevent one particular type of the bacterium (type B) not contained in the other meningococcal vaccines, are made using two or more proteins from the bacteria, not the bacterial polysaccharide.

Just like for inactivated viral vaccines, bacterial vaccines can be given to people with weakened immune systems, but often require several doses to induce adequate immunity.
5)- PROVIDE THE GENETIC CODE (DNA, MRNA, OR VECTORED VIRUSES) FOR PART OF THE VIRUS:
Using this strategy, the person who is vaccinated makes part of the virus. Some of the vaccines for COVID-19 are made this way.
6)- mRNA VACCINES:
The COVID-19 messenger RNA (mRNA) vaccine contains mRNA that is the code, or blueprint, for the spike protein of the SARS-CoV-2 virus. The vaccinated person’s dendritic cells use the blueprint to make the spike protein from the surface of the virus. Once the immune system realizes this protein is “foreign,” it creates an immune response against it, including immunologic memory, so the next time, the person is exposed to the virus, the immune system is ready to respond rapidly. Similar to vaccination strategies that inject parts of a virus directly, this strategy can be used when an immune response to one part of the virus is capable of protecting against disease.
These vaccines can be given to people who are immune-compromised but require two doses to be protective. The Pfizer and Moderna COVID-19 vaccines are made this way.
• Listen to Dr. Offit explain mRNA vaccines in this short video.
7)- DNA VACCINES:
DNA vaccines deliver the genetic code from which mRNA is made. The mRNA then serves as the blueprint for making the viral protein, and the immune system, recognizing it is “foreign,” responds to protect the body and create immunologic memory. Currently, no DNA vaccines are commercially available.
• Listen to Dr. Offit explain DNA vaccines in this short video.
8)- VECTOR VIRUS VACCINES (E.G., ADENOVIRUS-BASED VACCINES):
Another way to deliver the gene that codes for the coronavirus spike protein is to put that gene into a virus that can’t reproduce itself but can still enter cells and deliver the needed gene. This strategy is being used in so-called replication-deficient human or simian adenovirus vaccines. Although adenoviruses can cause disease in people, these vectored viruses are engineered so that they can’t cause disease; as such, they can be given to people who are immune-compromised.
The Johnson & Johnson/Janssen COVID-19 vaccine is made this way. It is given as one dose.
Reviewed by Paul A. Offit, MD on March 08, 2021
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…”A MUST READ”…!!! WHETHER WE LIKE VACCINES OR NOT, PLEASE READ THIS CAREFULLY BEFORE YOU TAKE YOUR FINAL DECISION TO OR...
03/05/2021

…”A MUST READ”…!!! WHETHER WE LIKE VACCINES OR NOT, PLEASE READ THIS CAREFULLY BEFORE YOU TAKE YOUR FINAL DECISION TO OR NOT TO EVER BE VACCINATED:
THE HISTORY OF VACCINES AND IMMUNIZATION: FAMILIAR PATTERNS, NEW CHALLENGES:
Excerpts from Alexandra Minna Stern, assistant professor in the Department of Obstetrics and Gynecology and Howard Markel Professor of the History of Medicine :
PREAMBLE:
If we could match the enormous scientific strides of the twentieth century with the political and economic investments of the nineteenth, the world’s citizens might be much healthier.
ABSTRACT:
Human beings have benefited from vaccines for more than two centuries. Yet the pathway to effective vaccines has been neither neat nor direct. This paper explores the history of vaccines and immunization, beginning with Edward Jenner’s creation of the world’s first vaccine for smallpox in the 1790s. We then demonstrate that many of the issues salient in Jenner’s era—such as the need for secure funding mechanisms, stream-lined manufacturing and safety concerns, and deep-seated public fears of inoculating agents—have frequently reappeared and have often dominated vaccine policies. We suggest that historical awareness can help inform viable long-term solutions to contemporary problems with vaccine research, production, and supply.
The gasping breath and distinctive sounds of whooping cough; the iron lungs and braces designed for children paralyzed by polio; and the devastating birth defects caused by rubella: To most Americans, these infectious scourges simultaneously inspire dread and represent obscure maladies of years past. Yet a little more than a century ago, the U.S. infant mortality rate was a staggering 20 percent, and the childhood mortality rate before age five was another disconcerting 20 percent. Not surprisingly, in an epoch before the existence of preventive methods and effective therapies, infectious diseases such as measles, diphtheria, smallpox, and pertussis topped the list of childhood killers. Fortunately, many of these devastating diseases have been contained, especially in industrialized nations, because of the development and widespread distribution of safe, effective, and affordable vaccines. Indeed, if you asked a public health professional to draw up a top-ten list of the achievements of the past century, he or she would be hard pressed not to rank immunization first. Millions of lives have been saved and microbes stopped in their tracks before they could have a chance to wreak havoc. In short, the vaccine represents the single greatest promise of biomedicine: disease prevention.
Nevertheless, the story is more complicated than it might appear at first glance. Even as existing vaccines continue to exert their immunological power and new vaccines offer similar hopes, reemerging and newly emerging infectious diseases threaten the dramatic progress made. Furthermore, obstacles have long stood in the way of the production of safe and effective vaccines. The historical record shows that the development of vaccines has consistently involved sizable doses of ingenuity, political skill, and irreproachable scientific methods. When one or more of these has been lacking or perceived to be lacking, vaccination has engendered responses ranging from a revised experimental approach in the laboratory to a supply shortage and even insurrection in the streets. In short, vaccines are powerful medical interventions that induce powerful biological, social, and cultural reactions.
EDWARD JENNER, COWPOX, AND SMALLPOX VACCINATION:
We begin our history of vaccines and immunization with the story of Edward Jenner, a country doctor living in Berkeley (Gloucestershire), England, who in 1796 performed the world’s first vaccination. Taking pus from a cowpox lesion l on a milkmaid’s hand, Jenner inoculated an eight-year-old boy, James Phipps. Six weeks later Jenner variolated two sites on Phipps’s arm with smallpox, yet theboy was unaffected by this as well as subsequent exposures.5Basedontwelvesuch experiments and sixteen additional case histories he had collected since the1770s, Jenner published at his own expense a volume that swiftly became a classic text in the annals of medicine: Inquiry into the Causes and Effects of the Variolae Vaccine. His assertion “that the cow-pox protects the human constitution from the infection of smallpox” laid the foundation for modern vaccinology.6How did Jenner, a country doctor, formulate the vaccine concept? To begin with, his discovery relied extensively on knowledge of the local customs of farming communities and the awareness that milkmaids infected with cowpox, visible as pustules on the hand or forearm, were immune to subsequent outbreaks of smallpox that periodically swept through the area. Moreover, a learned man immersed in the secular and rational doctrines of the Enlightenment, Jenner applied the scientific methods of observation and experimentation to this parochial wisdom, ultimately conducting one of the world’s first clinical trials. He thus wasable to devise an alternative to variolation (the controlled transfer of pus from one person’s active smallpox lesion to another person’s arm, usually subcutaneously with a lancet),which had been practiced in Asia since the 1600s and in Europe and colonial America since the early 1700s. Jenner also profited from his training as a wide-ranging generalist with a broad knowledge of science and medicine. For example, before devoting himself to private practice, Jenner focused on natural history, penning well-respected studies of the cuckoo and the dormouse.8In fact, Jenner was so skilled a naturalist that he was invited (although he declined) to join Captain Cook’s second voyage to the South Seas to classify flora and fauna. Jenner’s interest in natural history and animal biology sharpened his medical understanding of the role of human-animal trans-species boundaries in disease transmission. He experienced the proverbial “Eureka”-like moment sometime during the 1770s, after hearing a Bristol milkmaid boast, “I shall never have small-pox for I have had cowpox. I shall never have an ugly pockmarked face.”Tw o decades later he translated that farming lore into the guiding principle of his cow-pox inoculation hypothesis. His cognizance that animals were implicated and necessary for vaccine production was truly prescient; it foreshadowed later use of cows, guinea pigs, rabbits, and even chicken eggs in vaccine production. How-ever, this breach of the species barrier also made many people wary of and some-times hostile to the idea of consciously introducing foreign animal products into their own bodies. During the early 1800s, for example, there was no shortage of cartoons mocking Jenner and depicting the transmogrification of the recently vaccinated into sickly cows and fantastical beasts.10nBeyond cowpox. Although Jenner’s milkmaid experiments may now seem like quaint fables, they provided the scientific basis for vaccinology. This is all the more striking given that our current conceptions of vaccine development and therapy are now much more encompassing and firmly rooted in the science of immunology. Until the brilliant French chemist Louis Pasteur developed what he called a rabies vac-cine in 1885, vaccines referred only to cowpox inoculation for smallpox. Although what Pasteur actually produced was a rabies antitoxin that functioned as a post-infection antidote only because of the long incubation period of the rabies germ, he expanded the term beyond its Latin association with cows and cowpox to include all inoculating agents.11Thus, we largely have Pasteur to thank for today’s definition of vaccine as a “suspension of live (usually attenuated) or inactivated microorganisms(e.g., bacteria or viruses) or fractions thereof administered to induce immunity and prevent infectious disease or its sequelae.” in Changing terminology, constant challenges. Even though vaccination and immunization are often used interchangeably, especially in nonmedical parlance, the latter is a more inclusive term because it implies that the administration of an immunologic agent actually results in the development of adequate immunity. As the definitions of vaccine, vaccination, and andimmunizationhave changed overtime, becoming more scientifically precise, many of the basic patterns and problems of vaccinology have remained constant. In particular, issues of funding have been central to the steady development and distribution of vaccines, as have concerns with contamination and safety. Furthermore, public reactions to vaccines are usually quite strong, even as they have varied from awe of a seeming scientific miracle to skepticism and outright hostility. Beyond the far-reaching microbiological and immunological discoveries that have transformed vaccinology over the past century, vaccinology has been shaped increasingly by regulations governing human-subjects research and the enforcement of sterilization and safety standards. Especially after World War II, as exemplified by the exacting standards demanded by Thomas Francis Jr. in the polio field trials of 1954, the ethical design and ex*****on of vaccine research has become a core concern for many stakeholders.
WHAT ARE VACCINES?
By Michael Woods, MD, FAAP :
A vaccine is a biological substance designed to protect humans from infections caused by bacteria and viruses. Vaccines are also called immunizations because they take advantage of our natural immune system’s ability to prevent infectious illness. To understand how vaccines work, we need to consider how our immune system protects us from infections.
THE IMMUNE SYSTEM:
The immune system is a 24-hour machine equipped to manage attacks from invaders to prevent or inhibit infections. It is made up of organs, tissues, and several types of cells that work together to protect the body. The immune cells must be able to determine which cells or proteins are normally in the body and which ones are foreign. Bacterial and viral cells have markers called antigens. Antigens are capable of inducing an immune response in the body. Each type of bacteria or virus has different antigens.
First, in the presence of foreign cells or proteins that may cause danger, special immune cells called lymphocytes, become active. They take steps against the antigen and its owner, either by unleashing a direct assault on the invader or discharging antibodies to do the job. Think of it as a lock and key system. Specific antibodies take out specific antigens.
After an infection, sometimes the antibodies remain in the blood and will begin to fight the infection right away if you are exposed to it again. At other times they do not. However, the next time the antigen is identified, the body recognizes them (memory) and begins to make antibodies against it. Common symptoms, like a sore throat or fever, may be present until the immune system catches up with the invaders. A fever is one way the body fights invaders.
The immune system, while efficient, is specific. It is designed to promote future or long-term immunity to individual organisms. One example is the seasonal flu. Have you ever wondered why you or someone else gets the flu every year, even when you have had it before? The answer is that there are many different strains of the influenza virus that get passed around each season. These different strains all have different antigens. Being immune to last year’s flu strain may protect you for the duration of the season, but it will be of little use when next year’s strains come around.
That's why vaccines are useful and important. They are designed to create defenses against specific diseases before you even get them and help you stay healthy.
HOW VACCINES FIT IN:
The concept behind vaccines is to stimulate an antibody memory response without producing an actual illness. When this happens, you get the immunity without getting sick. A vaccine must contain at least one antigen from the bacteria or virus in order to get a response.
THERE ARE SEVERAL WAYS AN ANTIGEN CAN BE USED:
• Attenuated live viruses—Weakened forms of a live virus. They do not cause illness, but will create an immune response. Examples include the MMR (measles, mumps, rubella) and chickenpox vaccines.
• Inactivated viruses—A version of the virus that has been killed. Although the virus is dead, antibodies will still be produced. Examples include the polio vaccine.
• Recombinant—Viruses are made in a lab through genetic engineering. This way, a specific gene can be reproduced. The human papillomavirus (HPV) has several strains. The HPV vaccine can be tailored to protect against strains that cause cervical cancer.
• Conjugate—Bacteria and virus antigens may have a polysaccharide coating, a sugar-like substance to protect it. Conjugate vaccines work around the disguise to recognize the bacteria. The Hib vaccine is an example of a conjugate.
• Subunit—Uses only the antigens that stimulate an immune response. The flu shot is a subunit vaccine.
• Toxiod—Inactivated versions of bacterial toxins are used to make the immunity. Examples include the teta**s and diphtheria vaccines.
The presence of a vaccine in the body causes the immune system to produce antibodies against the invading antigens. Usually, it takes more than one vaccine to attain a full response. Most are done in a series of vaccines that are given at specific intervals of time. Some, such as teta**s, may need to redone periodically to maintain immunity (a booster).
Reduction in immunity over time can cause outbreaks of disease in a group or community of people who no longer have immunity. This happens periodically with mumps outbreaks on college campuses or in cases of pertussis (whooping cough) in adults. Outbreaks can also occur because of lapses in booster doses or in areas where vaccination rates are low. Increases in the rates of whooping cough, measles, and mumps result from these lapses.
VACCINES CAN BE:
• Injected (most common)—a needle is inserted into a muscle or just under the skin
• Oral—taken by mouth
• Intranasal—inhaled through the nose
VACCINES TO PREVENT OTHER DISEASES:
All vaccines are designed to target infections. However, two commonly recommended vaccines have the added benefit of protecting against cancer:
• Hepatitis B—Because it is a cause of liver cancer and alcoholic cirrhosis, a hepatitis B vaccine can help protect you against these liver diseases. There is also a vaccine available for hepatitis A.
• HPV—The leading cause of cervical cancer and the precancerous cervical dysplasia in females. In males, different types of HPV can cause ge***al warts. Others types can cause cancers of the p***s, a**s, and back of the mouth and throat.
THE IMPORTANCE OF VACCINATION:
Vaccines have been around long enough that many young people and parents are unaware of the devastation that infectious disease has caused around the world. Most diseases that used to kill or disable so many people are not present in the US any longer. Because of this, many people think that these vaccines are no longer needed. This is not so because most of these diseases can be found in other parts of the world.
One notorious, highly contagious disease left its mark on human history for 3,000 years before it was eradicated through vaccination. Smallpox infected 50 million people worldwide every year and killed nearly a third of those who contracted it. Survivors were left with disfiguring skin lesions (even on the face), total blindness, or both. In 1979, thanks to a global effort, 50 million cases of smallpox per year was eventually reduced to zero. Many other vaccine-preventable diseases have seen dramatic drops in infection rates. Polio is likely to be eradicated in the next few years.
To completely eradicate an infectious illness, high vaccination rates are necessary. For example, if a non-vaccinated person with measles enters a new community, they will have no impact on that community if all of its members are already immune to measles. This is called herd immunity. The concept of global vaccination and herd immunity may lull you into thinking your child is protected because of others, but this is not true. We live in a global community where people with serious infections can get around the world in a matter of hours. It does not take long for a contagious disease to spread among people who are unprotected. This has occurred recently with outbreaks of measles and mumps. Both diseases have serious health complications.
Keep in mind that vaccinating your child will protect others as well. People in certain populations or infants may not be able to get a vaccine. Having your child vaccinated protects your child and anyone they come in contact with.
SAFETY AND CONTROVERSY:
Vaccine safety has been a concern since they have been available, so the controversies are not new. Over the years, some vaccines have been recalled or linked to other heath conditions. Unvalidated information can lead others to think vaccines cause more harm than good, and this is not the case. Although there are some risks involved in getting vaccinated, they are overwhelmingly safe. The most recent public controversy concerns the MMR vaccine and its link to autism, a developmental disability. There was one, now retracted, study that showed this. However, there have been numerous studies since then that prove there is no link, but the negativity surrounding MMR safety persists.
As a parent, you need to have all the facts before you make a decision. Learn what ingredients are used to make a vaccine, the disease's history, and how it can affect your child and those around your child.
Most everyone, from infancy to adulthood, can be vaccinated. There are some considerations for certain populations, like transplant recipients or those with suppressed immune systems. These can be addressed on an individual basis.
Have an open, honest discussion with your child's doctor to address any concerns you may have about vaccination.
I THANK YOU.
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BEFORE YOU MARRY, ALWAYS MAKE A GENOTYPE COMPATIBILITY TEST TO AVOID SICKLE CELL TRAITS:Genotype can be simply defined a...
28/03/2021

BEFORE YOU MARRY, ALWAYS MAKE A GENOTYPE COMPATIBILITY TEST TO AVOID SICKLE CELL TRAITS:
Genotype can be simply defined as the genetic constitution of an individual organism.
This is different from your phenotype which is a description of your actual physical characteristics. It is imperative to know your genotype before you say “yes” to that handsome guy or to that beautiful lady whom you wish to spend the rest of your life with or if you are in a relationship in which there are chances of conception.

The problem to avoid with genotype compatibility for intending couples is the sickle cell disease (a recessive disorder)--a very serious medical condition with high prevalence rates in Africa south of the Sahara.

TYPES OF GENOTYPE:

The genotypes in humans are AA, AS, AC, SS. They refer to the hemoglobin gene constituents on the red blood cells. AC is rare whereas AS and AC are abnormal.
Genotype Compatibility Chart
Study this table below carefully:
AA + AA = AA, AA, AA, AA (Excellent)
AA + AS = AA, AS, AA, AS, (Good)
AA + SS = AS, AS, AS, AS, (Fair)
AA + AC = AA, AA, AA, AC. (Good)
AS + AS = AA, AS, AS, SS, (Very Bad)
AS + SS = AS, SS, SS, SS, (Very Bad)
AS + AC = AA, AC, AS,SS. (Bad; Advice needed)
SS + SS = SS, SS, SS, SS, (Very Bad)
AC + SS = AS, AS, SS, SS, (Very Bad)
AC + AC = AA, AC, AC, SS. ( Bad; Advice needed)

COMPATIBLE GENOTYPES FOR MARRIAGE ARE:
AA marries an AA. That’s the best compatible. That way you save your future children the worry about genotype compatibility.
AA marries an AS. You’ll end up with kids with AA and AS which is good. But sometimes if you’re not lucky all the kids will be AS which limits their choice of partner.
AS and AS should not marry, there is every chance of having a child with SS.
AS and SS shouldn’t think of marrying.
And definitely, SS and SS must not marry since there’s absolutely no chance of escaping having a child with the sickle cell disease.

SOLUTION:
The only thing that can change the genotype is the bone marrow transplant (BMT). It has been proven to be the only promising permanent cure to SS, SC, and CC; however, it is new, very expensive and cannot be done in any part of Africa. It also carries some risks.

WHAT, IN THE NUTSHELL, IS IONIZING RADIATION AND/OR RADIOBIOLOGY?Exposure to ionizing radiation causes damage to living ...
25/01/2021

WHAT, IN THE NUTSHELL, IS IONIZING RADIATION AND/OR RADIOBIOLOGY?
Exposure to ionizing radiation causes damage to living tissue and can result in radiation burns, cell damage, radiation sickness, cancer, and death.
Radiobiology (also known as radiation biology, and uncommonly as actinobiology) is a field of clinical and basic medical sciences that involves the study of the action of ionizing radiation on living things, especially health effects of radiation. Ionizing radiation is generally harmful and potentially lethal to living things but can have health benefits in radiation therapy for the treatment of cancer and thyrotoxicosis. Its most common impact is the induction of cancer with a latent period of years or decades after exposure. High doses can cause visually dramatic radiation burns, and/or rapid fatality through acute radiation syndrome. Controlled doses are used for medical imaging and radiotherapy.
HEALTH EFFECTS:
In general, ionizing radiation is harmful and potentially lethal to living beings but can have health benefits in radiation therapy for the treatment of cancer and thyrotoxicosis.
Most adverse health effects of radiation exposure may be grouped in two general categories:
• deterministic effects (harmful tissue reactions) due in large part to the killing/ malfunction of cells following high doses; and
• stochastic effects, i.e., cancer and heritable effects involving either cancer development in exposed individuals owing to mutation of somatic cells or heritable disease in their offspring owing to mutation of reproductive (germ) cells.
STOCHASTIC:
Some effects of ionizing radiation on human health are stochastic, meaning that their probability of occurrence increases with dose, while the severity is independent of dose. Radiation-induced cancer, teratogenesis, cognitive decline, and heart disease are all examples of stochastic effects.
Its most common impact is the stochastic induction of cancer with a latent period of years or decades after exposure. The mechanism by which this occurs is well understood, but quantitative models predicting the level of risk remain controversial. The most widely accepted model posits that the incidence of cancers due to ionizing radiation increases linearly with effective radiation dose at a rate of 5.5% per sievert. If this linear model is correct, then natural background radiation is the most hazardous source of radiation to general public health, followed by medical imaging as a close second. Other stochastic effects of ionizing radiation are teratogenesis, cognitive decline, and heart disease.
Quantitative data on the effects of ionizing radiation on human health is relatively limited compared to other medical conditions because of the low number of cases to date, and because of the stochastic nature of some of the effects. Stochastic effects can only be measured through large epidemiological studies where enough data has been collected to remove confounding factors such as smoking habits and other lifestyle factors. The richest source of high-quality data comes from the study of Japanese atomic bomb survivors. In vitro and animal experiments are informative, but radioresistance varies greatly across species.
The added lifetime risk of developing cancer by a single abdominal CT of 8 mSv is estimated to be 0.05%, or 1 one in 2,000.
DETERMINISTIC:
ACUTE RADIATION SYNDROME:
Deterministic effects are those that reliably occur above a threshold dose, and their severity increases with dose.
High radiation dose gives rise to deterministic effects which reliably occur above a threshold, and their severity increases with dose. Deterministic effects are not necessarily more or less serious than stochastic effects; either can ultimately lead to a temporary nuisance or a fatality. Examples of deterministic effects are:
• Acute radiation syndrome, by acute whole-body radiation
• Radiation burns, from radiation to a particular body surface
• Radiation-induced thyroiditis, a potential side effect from radiation treatment against hyperthyroidism
• Chronic radiation syndrome, from long-term radiation.
• Radiation-induced lung injury, from for example radiation therapy to the lungs
• Cataracts, and infertility.
The US National Academy of Sciences Biological Effects of Ionizing Radiation Committee "has concluded that there is no compelling evidence to indicate a dose threshold below which the risk of tumor induction is zero".
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium.[1][2] This includes:
• electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ)
• particle radiation, such as alpha radiation (α), beta radiation (β),proton radiation and neutron radiation (particles of non-zero rest energy)
• acoustic radiation, such as ultrasound, sound, and seismic waves (dependent on a physical transmission medium)
• gravitational radiation, radiation that takes the form of gravitational waves, or ripples in the curvature of spacetime.
Radiation is often categorized as either ionizing or non-ionizing depending on the energy of the radiated particles. Ionizing radiation carries more than 10 eV, which is enough to ionize atoms and molecules and break chemical bonds. This is an important distinction due to the large difference in harmfulness to living organisms. A common source of ionizing radiation is radioactive materials that emit α, β, or γ radiation, consisting of helium nuclei, electrons or positrons, and photons, respectively. Other sources include X-rays from medical radiography examinations and muons, mesons, positrons, neutrons and other particles that constitute the secondary cosmic rays that are produced after primary cosmic rays interact with Earth's atmosphere.
Gamma rays, X-rays and the higher energy range of ultraviolet light constitute the ionizing part of the electromagnetic spectrum. The word "ionize" refers to the breaking of one or more electrons away from an atom, an action that requires the relatively high energies that these electromagnetic waves supply. Further down the spectrum, the non-ionizing lower energies of the lower ultraviolet spectrum cannot ionize atoms, but can disrupt the inter-atomic bonds which form molecules, thereby breaking down molecules rather than atoms; a good example of this is sunburn caused by long-wavelength solar ultraviolet. The waves of longer wavelength than UV in visible light, infrared and microwave frequencies cannot break bonds but can cause vibrations in the bonds which are sensed as heat. Radio wavelengths and below generally are not regarded as harmful to biological systems. These are not sharp delineations of the energies; there is some overlap in the effects of specific frequencies.
The word radiation arises from the phenomenon of waves radiating (i.e., traveling outward in all directions) from a source. This aspect leads to a system of measurements and physical units that are applicable to all types of radiation. Because such radiation expands as it passes through space, and as its energy is conserved (in vacuum), the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source. Like any ideal law, the inverse-square law approximates a measured radiation intensity to the extent that the source approximates a geometric point.
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