Helicobacter pylori is, by bacteriological standards, a relative newcomer to medicine. Although its pathogenesis has been studied for only about the past 20 years, there are reports from as far back as the late 19th century of small, helical bacteria in the stomachs of some patients. Largely these anecdotal reports were relegated to the “hmm, interesting” file and not followed up for many years. It wasn’t necessarily that others didn’t follow (or care about) the research; the lack of studies on them, despite occasional reports in the literature, is probably due more to the fact that we hadn’t figured out yet how to culture them outside of the body. Prior to the era of molecular biology, this made studies of bacteria such as Helicobacter difficult, if not impossible.
However, studies began in the late 1970s by Robin Warren and Barry Marshall led initially to the culture of Helicobacter pylori (previously designated Vibrio rugula and Campylobacter pylori) from human stomachs–and a quarter-century later, a Nobel prize for their discovery and subsequent work showing the relationship between Helicobacter pylori and gastritis and gastric ulcer disease. The bacterium has also been shown to play a role in the development of several types of gastric cancers.
Additionally, Helicobacter research has extended far beyond the stomach, providing clues about the development of other diseases and even human migration. I’ll write more about these topics later this week, highlighting two new papers featuring this fascinating gastric bacterium.
Image from http://upload.wikimedia.org/wikipedia/commons/d/d6/EMpylori.jpg
This is the third of 6 guest posts on infection and chronic disease.
Does chronic IL-6 levels lead to epigenetic changes in DNA methylation that contribute to this pathway?
By Matthew Fitzgerald
How can infection be a carcinogen?
How do infectious diseases lead to cancer, if at all, is still a highly debated area of research. Do infectious diseases change the genetic information by insertions, mutation, or do bacterial toxins act as carcinogens? Does inflammation lead to free radical damage and cancer? While all of these and more are possible causes, another potential mechanism is that infection could change the epigenetics of cells at the site of infection. What is epigenetics? It is how our genetic information is controlled to tell cells what genes should be expressed and what genes should be silenced. For example what tells a stem cell to become a heart cell or kidney cell? Both contain the exact same DNA but are different because they express different genes, this is epigenetics.
(More after the jump…)
Continue reading “Infectious Disease-Chronic Inflammation-Cancer”
It’s just not been Vegas’ week. First a ricin-laced hotel room, then a clinic-associated outbreak of hepatitis C virus (and potentially hepatitis B and HIV) that could become enormous. Meanwhile, an outbreak of hepatitis E is raging in Uganda. So what are these virues, and how in the world could a medical catastrophe of this magnitude happen in the U.S.? More after the jump…
Continue reading “The ABCs (and DEGs) of hepatitis viruses”
This is the sixth of 6 guest posts on infectious causes of chronic disease.
By Ousmane Diallo
I was dumbfounded when I read this news article relating HPV to the increase of lip and oral cancers because of oral sex.
It reminded me my younger years, as a med student, debating with my professor of psychology the fundamentals of Freudian psychoanalysis, the Id, the Ego and the Super-ego. It was a rather philosophical debate more than anything else, a combination of religious and cultural reciprocal statements of beliefs. At that time, we were exposed to the new French “sexual education” magazine called Union, borderline Playboy and X-rated. Even though we were colonized for one hundred years, sang the Marseillaise at elementary school, believed like the Koran that we were the descendants of the Gallic people, Fellation and Cunulingus amounted to blasphemy; even French kisses were of an oddity. As a true disciple of Freud, my professor believed that our Islamic beliefs system enmeshed with the weight of African ancestral traditions were at the cornerstone of the decadence of African societies, the social disconnect with the desire of every individual to be free from the yoke of group. No wonder why, he said, we were seeing more and more drug addiction (mostly Marijuana), schizophrenics, histrionics and all the ills of proto-modern, transitional, societies. The main thing was that humans needed to free themselves from society, break the ego free from the super-ego or at least limit its nefarious effects on the development of man’s personality. Only by using the old Marxist exercise of criticism on Taboos could we, as humans, attain Nirvana, Felicity, Bliss or Paradise, “here on Earth and not over there in Heaven” (Karl Marx, 1883). The only thing I could utter was that if he really believed that man should only follow his desires, mate as he wished and how he wanted to, and behave like animals, then let him be aware of God’s wrath; “He will strike humanity with unknown diseases”, quoting the religious text. Instead of good grades, I earned a nickname “Ayatollah”.
(More after the jump…)
Continue reading “Behaviors, Human Papilloma Virus and Sex Act Cancers”
This is the first of 6 guest posts on infectious causes of chronic disease.
by Matthew Fitzgerald
Viruses cause cancer?
Cancer researchers have for decades known that viruses can cause cancer. It is now estimated that 15% of the world’s cancers are caused by infectious diseases including viruses. Some of these include: Human Papilloma Virus (HPV) and cervical cancer; Epstein-Barr Virus (EBV) and nasopharyngeal cancer & lymphoma; Hepatitis B and liver cancer. In fact cancer researchers use this knowledge of viruses causing cancer by utilizing EBV and SV40 and other viruses to “immortalize” cells in their labs to have better cancer models. These “immortalized” cells keep dividing and act like cancer cells so that researchers can continually propagate their experiments. It is believed these viruses interfere with oncogenes and tumor suppressor genes in the cells. These important genes act as the biological stop signs for cells to control their growth.
Can vaccines prevent cancer?
The simple answer is yes. It has been well documented that use of the Hepatitis B vaccine can significantly reduce the incidence of liver cancer. This success has lead other scientists to investigate whether new vaccines can prevent other forms of cancer. One of these other cancers is cervical cancer. Merck has introduced Gardasil that vaccinates women against 4 types of HPV types 6, 18, 16 and 11. These HPV types are believed to be responsible for 70% of all cervical cancers.
Continue reading “Could the Cervical Cancer Vaccine Gardasil also Protect against Breast Cancer?”
Last month, I wrote an update on the strange cancer affecting Tasmanian devils–a tumor cell that’s taken on a life of its own, and is spreading through the population as the animals fight. Now, via PZ comes something you can do to help–donate and help to save this species:
Help the Tasmanian devil with 6 top funding priorities:
1. Investigating the tumour and its chromosomes, looking for clues to resistance
2.Keeping some area or areas of Tasmania free from the disease i.e. wild management
3.Maintaining backup captive populations of devils in Tasmania as ‘insurance’
4.Developing a diagnostic test for the disease
5.Developing a vaccine against the disease
6.Monitoring changes in populations affected by the disease
Following a new PNAS paper regarding the strange facial cancers in Tasmanian devils, I have a post on the topic up over at Correlations. (Be sure to check out the Correlations homepage too!)
Last year, I mentioned some ongoing research suggesting a link between exposure to light and the development of breast cancer. As I mentioned then:
While we know a good deal about factors that can contribute to breast cancer risk–including genetics (such as mutations in the BRCA1 and BRCA2 genes) and lifestyle choices (late or no childbearing, high fat diet, lack of exercise), many environmental risks for breast cancer remain controversial. Even the effect of cigarette smoking on breast cancer development remains uncertain, as does the environmental light idea.
For a nice update and overview into the whole area, check out the story in today’s Chronicle by Richard Monastersky:
Continue reading “The perils of being a night owl”
A few readers have asked me what I thought about HIV “dissident” Peter Duesberg’s recent article in Scientific American, entitled Chromosomal Chaos and Cancer. Duesberg’s cancer ideas–and his claim of novelty for researching how chromosomal abnormalities, rather than more simpler gene mutations, cause cancer–are something I wanted to write about months ago, after I came across an interesting reference in this post over at Panda’s Thumb, where it was noted that “…in certain kinds of cancer, chromosomal instability prevents tumourogenesis, the exact opposite of what Wells [and Duesberg–TS] predicted.”
However, I simply haven’t had a lot of time to delve into this issue, since while I do actually have some training in the molecular pathogenesis of cancer, it’s not an area where I routinely keep up with the literature. However, the recent article also intrigued Orac, who, for those unfamiliar, is a cancer surgeon and carries out research into the molecular biology of cancer. He has a post up on the article today, and while he gets much more deeply into it, his general conclusion is in agreement with my first impression. A few money quotes:
Continue reading “Duesberg on cancer, deconstructed”
Last summer, I mentioned that groups receiving federal funding were providing misleading information about abortion, including the unsupported statement that having an abortion increases the risk of development of breast cancer. As I noted, this “link” has been refuted by a number of analyses, including a 2004 Lancet paper and a 2003 National Cancer Institute report. As if those weren’t enough, a new study comes to the same conclusion: yep, no link. More after the jump.
Continue reading “Yet another study shows no link between abortion and breast cancer”