Category Archives: Biological Sciences

Feces combats Clostridium difficile

Clostridium difficile or C-diff is a bacterium that 5-10% of the population have in their intestine as part of their normal flora, which is the intestinal composition of ‘good’ usually non-disease causing bacteria. In hospital settings, the amount of people that have C-diff in their intestine rises to 25%. C-diff is of particular concern in hospitals since there is a greater potential for patient to patient C-diff spread.

C-diff

Clostridium difficile - By: AJC1 via flickr

Some antibiotic treatments destroy the normal flora, however C-diff is a spore former, so it is not killed by many antibiotics. The absence of most of the normal flora allows for C-diff to germinate and grow – this produces toxins!  These toxins damage the mucus lining of the colon, which results in ulcers and layers of debris that leads to frequent diarrhea. The disease, called pseudomembranous colitis, can be fatal but is treatable with the powerful and costly antibiotic, Vancomycin. Despite treatment, there is still a high relapse rate of 10-20%.

A news article from The Seattle Times published that American doctors, including Dr. Lawrence Brandt and Dr. Christina Surawicz, have transplanted feces from a healthy person to a sick patient’s colon to combat C-diff and repopulate normal flora. Rest assured, the donors of the stool transplant are close relatives of the sick patient. The doctors of the news article claimed to have so far met success with this unconventional treatment. However, fecal transplants are not widespread and Dr. Brandt even noted that methods among doctors are inconsistent.

Locally, the CBC published an article indicating that the BC Fraser Health Authority had initially barred fecal transplants due to lack of study. I feel that this is currently reasonable until a greater amount of clinical trials are published. Of the published small scale case studies, one in 2009 obtained a  ~73% success rate with fecal transplants and later in 2010 another study posted 100% success. There is also a full clinical trial underway from the University Health Network in Toronto.

Dr. Jeanne Keegan-Henry speaks on fecal transplants:
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In my opinion, one of the issues of fecal transplants is that most of the published research is within the last two years. The long term effects of introducing a different composition of bacteria and potentially other things into a sick patient are not known. If full clinical trials continue to be successful, an antibiotic free treatment for C-diff would not only ease costs for patients, but also slow the development of multi-antibiotic resistant superbugs.

Cloning the Mammoth: It’s Big!

Will mammoths once again walk the earth? Photo - Flickr: Tracy O

Personally, when anyone talks about mammoths, which isn’t actually very often, I immediately think of Manny, the grumpy, but loveable, mammoth from Ice Age. However, Manny may soon be the second most well known mammoth around. Last month the headline: “Mammoth ‘could be reborn in four years’” was published in the British newspaper The Telegraph. Akira Iritani, a professor at Kyoto University, believes that we now have the technology to resurrect the giant mammal, and he wants to make it happen.

Until recently, cloning from frozen specimens was thought to be impossible. Ice crystals formed in the cell during freezing cause extensive damage, rendering cells unviable. However, in 2008, Dr. Teruhiko Wakayama and his team successfully cloned a mouse using mice that had been frozen for sixteen years. The trick was that they didn’t use whole cells, instead they searched for intact nuclei that hadn’t been damaged during freezing. The intact nuclei were inserted into mouse cells, from which the DNA had been removed, and implanted into a surrogate mother.

Cloning the mammoth could require as little as a few grams of soft-tissue from a frozen mammoth. Iritani plans to look for a specimen in the permafrost of Siberia this summer. After finding the tissue and isolating the viable nuclei, researchers will insert the nuclei into the egg of an African elephant and she will act as the surrogate mother for a gestation period of close to 600 days.

Cloning the mammoth would be an amazing scientific breakthrough, but this kind of science raises many concerns and I can’t help but wonder: Why we’re doing it?

In 2008, in the Guardian, Bill Holt, head of reproductive biology at the Zoological Society of London, raised the following concern: “You have to think about why you would do it and where you would put it”. Planet earth has changed drastically since the mammoth disappeared at the end of the last ice age. So I have to ask: Where will the new mammoth live? Will we clone more than one? Will they reproduce? If so, they will have a very small gene pool.

Given the limited number of viable nuclei, it seems unlikely to me that we will be able to bring the mammoth back for good. Even if we did, they would never be able to live free in the wild. So, as incredible as it would be to see a live wooly mammoth face to face, it seems counterproductive to bring back the mammoth when many other species on earth are also facing extinction. Why not spend our energy saving species that are still here, rather than trying to bring them back once their gone?

Be cautious if traveling south during reading break

A recent study in the journal Science, found that a parasite and a virus are teaming up to increase its ability to harm humans. [1]



Viral infections appear red in this photo of the parasite Leishmania; the parasites’ nuclei are blue. New evidence published in Science this week suggests that these infections may help Leishmania cause more harm when it infects animal and human hosts. (Credit: Nicolas Fasel, PhD, Univ. of Lausanne in Switzerland)

An infection, known as leishmaniasis, is caused by the parasite Leishmani. This disease is mainly spread by sand fly bites. Symptoms of this infection are, large skin lesions, fever, swelling of the spleen and liver, and, in more serious forms of the disease, disfigurement and death. According to the article, this disease affects over 12 million people worldwide. The article can be found here.

The virus infects hosts by a Trojan Horse technique. “The strategy of the “Trojan horse” as a mechanism of pathogenicity of intracellular microorganisms is, to avoid the immune system and its memory function cleverly, with phagocytosis of infected and apoptotic neutrophils by macrophages, employing the non-danger surface signals of apoptotic cells.” From Wikipedia.

How the virus is increasing the pathogenicity is a fascinating question for researches right now. It may open up new opportunities for finding its cure.

This is the first time I have ever heard of this disease. Although this disease seems very serious, and will never deter me from enjoying the sunny beaches of Central and Southern America.

  1. A. Ives, C. Ronet, F. Prevel, G. Ruzzante, S. Fuertes-Marraco, F. Schutz, H. Zangger, M. Revaz-Breton, L.-F. Lye, S. M. Hickerson, S. M. Beverley, H. Acha-Orbea, P. Launois, N. Fasel, S. Masina. Leishmania RNA Virus Controls the Severity of Mucocutaneous LeishmaniasisScience, 2011; 331 (6018): 775 DOI:10.1126/science.1199326

That Lovin’ Feeling

On Monday next week, the theme will be all about love. 

This feeling of love has been tied to more then just getting that butterfly sensation in your stomach. Love can now be described at a neurochemical level. Research  is explaining love thanks to a little chemical called dopamine.

Dopamine neurones account for less than 1% of the total neuronal population in the brain, but have great effect on its function (Mardeson, 2006). It is involved in the control of movement and the modivation for reward. Deficiency in this neurotransmitter is tied to such diseases as Parkinsons ( Mardeson, 2006).

Dopamine has also been found to be relevant to the social pairing of males and females in long and short term relationships (Curtis et al, 2006). I have friends who talk about how their relationships have changed from fun and amazing to boring and dull. It amazes me that such a transition could be due to a lack of dopamine stimulation. But fear not, this isn’t the outcome for every relationship. Discovery News has reported on a study done by Arthur Aron (a social neuroscientist at Stony Brook University in New York) and his colleagues who have found that people in long term relationships who are madly in love are not lying and that this feeling can last!

The study took 17 people who felt that they were in long term loving relationships. MRI brain-scans were done while they looked at photos of their lover and of strangers (who had similar features). Their scans were similar to those of  recently fallen in love people by having a high activity in the region of the brain which processes dopamine. There was also high activity in regions related to pair-bonding and attachment.Also when comparing scans of people in long term relationships who did not rate their feeling of love as highly as to those who do, had lower levels of activity in the dopamine processing portion of the brain. This little neurotransmitter has powerful affects on our emotions, feelings and relationships. Could a little boost in producing dopamine keep us all on clould 9?

So when you give a Valentine’s Day card this Monday, that feeling you get may not be so fleeting!

  • 1.Marsden, C. A. (2006). Dopamine: The rewarding years. British Journal of Pharmacology, 147(S1), S136-S144. doi:10.1038/sj.bjp.0706473
  • 2.Curtis, J. T., Liu, Y., Wang, Z., & Aragona, B. J. (2006). Dopamine and monogamy. Brain Research, 1126(1), 76-90. doi:10.1016/j.brainres.2006.07.126