Infectious agents and cancer
10.29.09 by Sharmila Pejawar-Gaddy
Several cancers have been attributed to infectious agents. It is estimated that approximately 18% of all cancers worldwide are caused by infectious agents. 26% of these are in developing countries and 8% in developed countries. These figures and discrepancies between the developed and developing worlds point to differences in disease prevalence, either due to sanitary conditions or shortage of vaccines. Infectious agents can be classified as indirect or direct carcinogens. Indirect carcinogenic agents are those that cause chronic infection and thus chronic inflammation, which then leads to the advent of cancer. Examples of these include, Helicobacter pylori infection that is the an attributing factor to a majority of stomach/gastric cancers, as well as chronic hepatitis B and C infections that are causally linked to a majority of liver cancers. On the other hand, direct carcinogenic agents are those that can incorporate oncogenes into the cell’s genome. Examples of these are human papillomavirus that causes a majority of cervical cancers, as well as in some cases, penile cancer, vaginal cancer and genital warts; Epstein-Barr virus linked to a majority of Naso-pharengeal carcinomas and human herpes virus-8 linked to Kaposi’s sarcoma. This list grows every day. The good news is this: most of these infections, and thus the advent of several cancers, can be prevented by vaccination.
Adapted from Parkin, DM. 2006. Int J Cancer. 118:3030 and Dr. Douglas Lowy
Related articles
- Parkin, DM. 2006. The global health burden of infection-associated cancers in the year 2002. Int J Cancer. 118:3030.
- Campbell, K. 2006. The infectious causes of cancer. Nurs Times. 102(33):28.
- FDA approves Gardasil to prevent genital warts in boys (ctv.ca)
- FDA Approves Merck’s Gardasil for Boys (abcnews.go.com)
Fear the Flu More than the Flu Vaccine
10.20.09 by Daniel Gaddy
I have previously written on this site about the Influenza A(H1N1) virus and the possibility, however unlikely, of this virus becoming a catastrophic pandemic. In my first post, I was concerned that the general public was being driven toward unnecessary panic by a “media firestorm” of negative “swine flu” news coverage. Now, however, I have fears of the exact opposite. It seems that people may not be taking this virus seriously enough! As I said in my first article, we really do not know how deadly this virus will be, and the truth is that there is nothing about this virus, particularly its genome, that suggests it will be a catastrophic killer. However, influenza is always deadly and it needs to be taken seriously.
It seems that these days people are more terrified of vaccines than the diseases they are designed to prevent. This is, at least partially, due to a massive campaign to convince people that vaccines cause autism. However, there has been absolutely no scientific evidence of a vaccine-autism link. None. In relation to influenza vaccines, people are worried about a variety of issues, not the least of which is the speed at which the vaccine was produced and made available. An article in the NY Times last week by Paul Offit, a professor and expert on infectious diseases and vaccines at the University of Pennsylvania, addressed this and several other myths about the H1N1 vaccine.
…Here are some of those myths, and why they’re wrong:
Major breakthrough in stem cell therapeutics
10.11.09 by Atif Towheed
A team of Harvard Stem Cell Institute (HSCI) researchers have produced induced pluripotent (cells which have the capability to regenerate into any organ) stem (iPS) cells from adult cells.
…a patient with Parkinson’s disease might be treated with neurons created from his own cells, theoretically eliminating the need for immunosuppressive drugs, or the possibility of rejection of the transplanted cells. Similarly, patient-specific iPS cells could be used to create muscle for damaged hearts, or other individualized treatments.
http://www.sciencedaily.com/releases/2009/10/091008151715.htm
Measuring the Treatment of Evolution in Science Classes
08.13.09 by Daniel Gaddy
I recently wrote an Introduction to Evolution on this site outlining the basics of evolution and exploring the disconnect between the scientific community and the education system of the United States when it comes to the teaching of evolution. A new study by Louise Mead and Anton Mates, published in Evolution: Education and Outreach has performed a very thorough analysis of the teaching of evolution in science curricula, comparing each of the 50 states and the District of Columbia.
The authors compare their results to results of a similar analysis in 2000, which was referenced in my previous article. Essentially, 9 states (California, Florida, Indiana, Kansas, New Hampshire, New Jersey, New Mexico, Pennsylvania, and South Carolina) and the District of Columbia received grades of A, meaning the treatment of evolution in science classes was particularly good, while 5 states (Alabama, Louisiana, Oklahoma, Texas and West Virginia) received grades of F, meaning treatment of evolution was particularly poor. Kansas, in particular, is cited as a major success story. After several years of battling over standards for teaching evolution and intelligent design, Kansas “standards have improved immensely.”
While several states, including Kansas and Florida, improved their standards, several states, including Hawaii and Texas, actually regressed, often by the incorporation of creationist jargon. Overall conclusions from the study suggest that standards of teaching science in the United States public school system include more about evolution than in 2000. The authors also offer some advice on how to address science education standards in your state:
The Importance of Animal Research
08.7.09 by Daniel Gaddy
As a biomedical researcher, I firmly believe that the importance of animal research cannot be overstated. As eloquently expressed on the website of the Foundation for Biomedical Research:
Animal research has played a vital role in virtually every major medical advance of the last century – for both human and animal health. From antibiotics to blood transfusions, from dialysis to organ transplantation, from vaccinations to chemotherapy, bypass surgery and joint replacement, practically every present day protocol for the prevention, treatment, cure and control of disease, pain and suffering is based on knowledge attained through animal research.
Physicians and researchers overwhelmingly agree that animal systems provide invaluable and irreplaceable insights into human systems. The essential need for animal research is recognized and supported by medical societies and health agencies around the world.
Unfortunately, not everyone gets this point. Animal rights activists have fought for many years to end the legal and moral use of animals in research, or what they deem animal cruelty. The truth is, treatment of research animals in the United States is far from cruel. In fact, every institution in the United States that conducts animal research must establish an Institutional Animal Care and Use Committee, which oversees the use of animals in research and establishes guidelines that guarantee safe and ethical treatment of research animals.
As for the activists, they do not simply protest and voice their opinions. Animal rights activists are becoming increasingly violent. The video below describes a recent attack against Novartis:
A vacation home belonging to Novartis CEO Daniel Vasella was burned in a suspected arson, a week after his mother’s grave was vandalized by animal rights protesters. The words “Drop HLS Now” were spray painted on the grave, CNBC reports. The protesters want Novartis to sever its ties to Huntingdon Life Sciences, a contract company that does animal testing for drug companies.
The Obesity Epidemic
08.2.09 by Daniel Gaddy
The following is from an article in today’s Pittsburgh Post-Gazette describing the obesity epidemic in the United States and the repercussions on our current attempts at health care reform.
This article is very effective at stating the obvious: obesity is a growing problem in this country, and increasingly a problem around much of the developed world, but no one has any ideas of how to adequately address the issues. Just how bad is the problem?
The CDC estimates nearly 40 percent of American adults are considered obese based on their body mass index, a mathematical formula that considers a person’s height and weight. That extra weight frequently leads to additional health problems such as heart disease, diabetes, high blood pressure and pulmonary difficulties.
A RTI study estimates $1,429 a year is added to the nation’s health care costs for each obese patient. The overall cost is about 42 percent more annually for obese people and even higher for obese patients on Medicare. Obesity adds 9.1 percent to the annual cost of health care.
The truth is, far too many parties have too much invested in keeping America unhealthy. From the food industry to the health care industry, big profits are made when we are sick. The food is cheap, but poisoned by mass-production and cheap chemicals like high fructose corn syrup, which induces leptin resistance and leads directly to overeating.
The most expensive form of health care is treatment, while the most effective and inexpensive form is prevention. If the country wants to save money here, more effort needs to be placed on education and the prevention of obesity at an early age. Unfortunately, until fresh, healthy foods are cheaper than the unhealthy crap, far too many of us are going to continue to consume the poisons. If the poisons are all you can afford, at least they fill your belly! One part of the solution is to ban high fructose corn syrup or eliminate government corn subsidies, which would make the cost of high fructose corn syrup more than that of natural sugar. Another option on the table now is to tax soft drinks.
The Future of Brain Tumor Therapy
06.14.09 by Daniel Gaddy
A little over a year ago, the announcement that Senator Ted Kennedy was diagnosed with a malignant brain tumor brought a lot of attention to brain cancer research. Brain cancers are among the most perplexing types of cancers. Indeed, until now, it was not even known how brain cancers form. It was believed for many years that brain tumor metastasis, or the process whereby cancerous cells move from the location where a tumor has initially grown and spreads to other parts of the body, was the product of “brain-specific homing” of metastatic cancer cells from other areas of the body, followed by direct interactions of the cancer cells with neural tissues. However, recent research from Oxford University, published in the journal PLOS One, demonstrated that metastatic cancer cells in mouse and human tissue utilized “vascular cooption” for seeding brain tumors rather than invading and growing within the neural tissue. What this means is that cancer cells enter blood vessels, where they can then be transported throughout the body. This information is not new. What the Oxford researchers, led by Professor Ruth Muschel, showed is that once in the blood vessels, cancer cells can establish residence and begin to grow along the blood vessel walls. By thus co-opting blood vessels in the brain, tumors can utilize readily available nutrients and oxygen from the blood without having to grow their own blood vessels, which occurs via processes known as neovascularization and angiogenesis.
New Embryonic Stem Cell Policy
05.15.09 by Daniel Gaddy
New guidelines for the use of embryonic stem cells have been proposed by the National Institutes of Health. Many scientists were excited when President Barack Obama announced on March 9th that restrictions enforced by the Bush administration would be overturned. Under the Bush administration policy, only 21 embryonic stem cell lines that had been established prior to August 2001 qualified for federal funding. The new policy draft was released April 18th and, after much scrutiny from the science community, has been deemed by many scientists to be even more restrictive than the Bush administration policy.
The new policy requires consent forms that specifically mention human embryonic stem cell research, forbid donating eggs for the benefit of a specific person, and contain multiple other stipulations that were generally mentioned on older consent forms, but not specifically defined. The new rules are to be applied retroactively to existing embryonic stem cell lines, and therefore could have a serious impact on existing and proposed research. In fact, the vast majority of the 700+ existing embryonic stem cell lines would be ineligible for federal funding under the new policy.
The NIH has issued a Request for Comment in regards to the proposed “Draft National Institutes of Health Guidelines for Human Stem Cell Research Notice”. Prior to enacting these changes, the NIH must obtain public comment. These comments are taken seriously in determining whether the proposed changes will be enacted.
Stem cell research has been a hotly debated issue and responding to the request for comment is a way for individuals, scientists and lay-persons, to have a say in the discussion. We encourage you to make your voice heard.
The deadline for a response is May 26, 2009. The notice can be found at: http://edocket.access.gpo.gov/2009/E9-9313.htm. You may submit a comment through the following website: http://nihoerextra.nih.gov/stem_cells/add.htm.
Cancer vaccines: a brief introduction
05.8.09 by Sharmila Pejawar-Gaddy
From the time of the first documented vaccine against smallpox by Edward Jenner, developing an effective vaccine to prevent deadly disease caused by existing or newly emerging pathogens has been the goal of many microbiologists and immunologists. With a single exception, that of the rabies vaccine, all vaccines developed previously have been prophylactic, meaning that they are administered in order to prevent the onset of disease. The concept of a vaccine has slowly evolved to currently include a therapeutic vaccine, meant to ameliorate an existing disease state by potentially strengthening an ongoing but not fully effective immune response against a pathogen. Further broadening of the concept of a vaccine has come about with the realization that in addition to eliciting an immune response where there was none, a vaccine could also be designed to change an existing immune response from one type to another. Most recently, vaccines are being considered not only for elicitation of immunity but also potentially for induction of tolerance [1, 2]. This concept has also increased potential targets of vaccines from diseases caused by pathogens to any disease that involves the immune system, such as cancer, autoimmunity and graft rejection. [3-6].
Challenges facing cancer vaccines
Choosing the right antigen and adjuvant are the sine qua non of an effective vaccine.
The “right” antigen: Antigens used in cancer vaccines should preferably be molecules that are different between normal cells and tumor cells ensuring that the immune response generated by vaccination will target for destruction antigen-bearing tumor cells and not normal cells [7, 8]. This requirement is satisfied more easily in the case of vaccines against pathogens because their antigens are all foreign to the host and thus immunity generated against them, in most instances, does not cross-react with normal host tissues. In cancer, most antigens are derived from mutated or modified self-proteins against which there is often a certain level of immune tolerance. This creates particular challenges for the appropriate design of vaccines that have to overcome this tolerance in order to elicit anti-tumor immunity without autoimmunity [9].
Influenza A(H1N1)
05.4.09 by Daniel Gaddy
A media firestorm has been unleashed over the last few weeks regarding the so-called “swine flu.” If you pay attention to CNN or any mainstream media outlet, you are bombarded with dire warnings and panic-inducing reports of swine flu deaths and the resulting mayhem. I want to write this post to put things into perspective. Keep in mind that the news outlets have one thing in mind: ratings. The more fear they can strike into you, the more likely you are to watch. This is not to say that there is no reason to be concerned. As with any influenza outbreak, the more you know, the better prepared you are to handle it. However, the media consistently compare the current outbreak with previous pandemics, particularly the 1918 pandemic. The chances of such a disastrous pandemic are rare. Here, I will explain why that is, as well as provide some insight into this disease and some resources that will help you prepare should you come into contact with anyone infected with influenza.
First of all, the nomenclature “swine flu” is inaccurate. I am not saying this because I have been paid by the pork lobby. The truth is, this virus is part swine, part avian, and part human. This description is, in and of itself, probably confusing for a lay-person. Influenza virus biology is too complicated to get into here in real detail. Basically, influenza virus has a segmented genome. These segments are similar to chromosomes in humans, in that they are nucleic acids (RNA in the case of flu) and each segment codes for a different viral protein. The process of segments from different strains of virus (eg. swine, avian and human) coming together to form a new strain of virus is called re-assortment. This occurs when multiple viruses infect the same cell, and a basic example is illustrated in the figure below. This process occurs frequently, particularly in animals such as pigs and birds, but rarely results in super-virulent strains of influenza.
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