Monday, 16 April 2012

A Sad Story, or Why Oleander and Giraffes Don't Mix

My partner recently forwarded me a news story from Tucson, Arizona, regarding the unfortunate death of a giraffe at the Reid Park Zoo.

Based on the article, it would appear that a giraffe was accidentally fed brush trimmings that included leaves from the ornamental plant Oleander (Nerium Oleander). Oleander is a rather common ornamental plant, and is indeed ubiquitous in and around Sydney. Indeed, my primary school in South-West Sydney has a large oleander tree in the rear playground.  The leaves bear a superficial resemblance to those of the olive plant (hence the name), and have rather pretty white/pink flowers. It is rather hardy as well, being drought tolerant and capable of withstanding mild frosts, and hence has found its niche as an ornamental plant.

Pretty. Also deadly. Pretty deadly, I suppose?

Sadly, oleander is also incredibly toxic, with the leaves, bark and sap all containing a class of compounds known as cadiac glycosides. For the giraffe in the above article, what can only be presumed as an innocent mistake by a zookeeper was ultimately fatal. The response of zoo officials, in "carefully considering removing all the Oleander that's surrounding the outside of the park" is understandable.

As mentioned, oleander contains cardiac glycosides, which include the chemical oleandrin (structure below):

Definitely not giraffe friendly...
Despite the above case, cardiac glycosides are useful chemicals, and in a medical setting are used to treat congestive heart failure and arrhythmia. This use is mediated by inhibition of the sodium-potassium ion pumps present in cell membranes, which ultimately leads to an increased intracellular concentration of calcium. This, in turn, improves the force of contraction by cardiac muscle, improving cardiac output.

Unfortunately, compounds like oleandrin can also be insidiously toxic, with high doses capable of decreasing cardiac function and reducing the availability of oxygen to the tissues of the body. Without treatment, this can most certainly be fatal. Multiple cases of deaths due to ingestion (accidental or otherwise) ingestion of oleander and preparations of its leaves.  In 2000, two toddlers, aged two and three years old, died as a result of ingesting the leaves. This case is in itself unusual, as the leaves are reported to have an incredibly bitter taste, with Dr. Clarke, a medical toxicologist and director of the California Poison Control Centre, commenting that "There is not a single other case in the American literature that I know of of people eating oleander leaves and dying...".

Similarly, in the Annals of Emergency Medicine, it is reported that in 1985, a woman died after drinking a herbal tea prepared from the leaves of Neruim oleander. The article itself is interesting, as it is alleged that the woman mistook the leaves of the oleander plant for those of eucalyptus. This mistake proved fatal, as within ten hours the woman was displaying symptoms of confusion and impaired cardiac function. Staff at the hospital identified the leaves as those of the oleander plant, and took appropriate measures to prevent death. However:

"...despite these measures... the patient's cardiac rhythm deteriorated to an agonal rhythm and then to asystole. A transthoracic pacemaker was inserted... but no ventricular capture or palpable pulse resulted, and the patient was pronounced dead"

Treatment options are available in cases of oleander poisoning. Often, anti-digoxin Fab is given, which is the anti-digoxin antibody fragment. This antibody is routinely given for digoxin poisoning, which is another cardiac glycoside found in Digitalis.

Deaths due to oleander poisoning are not only limited to humans and giraffes. From livestock, including cattle and horses, through to domestic animals including dogs, oleander represents a real danger. Even goats, reputed by an old wive's tale to eat almost anything, are not immune. In general, it would appear that people are not aware of the toxicity of plants, oleander or otherwise.

As a sidenote, I feel that it would be remiss of me not to note one very interesting area of research concerning oleandrin. In the past few years, there has been some promising research indicating the possibility that oleandrin may be an anti-cancer agent. It has been found that oleandrin mediates apoptosis in tumour cells, but not in primary cells. If true, this would indicate that oleandrin may work as an anti-cancer agent with minimal side effects at the required dose. In vitro studies have also demonstrated that oleandrin may aid in the treatment of a wide range of cancers, including leukemia, pancreatic cancer and prostate cancer.

That being said, this research is still only in its early stages. However, I will be cautiously waiting for further developments in this area. This should not be an excuse for anyone to attempt ingestion of oleander. I trust that such a disclaimer is not warranted, but just to be safe, I shall include it again:

Please don't eat/ingest oleander. It really isn't a good idea. I promise. 

Until next time,

Saturday, 7 April 2012

The War on Drugs - Press Release by Australia21

In recent days there has been a really fascinating media release from a think tank known as Australia 21. Described on their website as "... an independent, non-profit organisation whose core purpose is multidisciplinary research and inquiry on issues of strategic importance to Australia in the 21st century", Australia 21 has released their much-anticipated report on discussing the costs and benefits of any potential changes to Australia's policy on illicit drugs.

The report itself is rather controversial. Not only does it broach a subject that many people still find taboo in this day and age, it also has quite a controversial title: "The Prohibition of Illicit Drugs is Killing and Criminalising Our Children and We Are All Letting It Happen". Title notwithstanding, the report makes for fascinating reading, though I must admit that at the time of writing, I am only part way through reading it. What has been clear so far is that the release of this report has already lead to debate within the wider community over current legislation regarding illicit/recreational drugs. As mentioned in a previous post, this is a contentious issue that, unfortunately, tends to be political suicide for those willing to bring it up for discussion and debate.

At any rate, the fact that drug legalisation and drug policy is once again being discussed does give one hope that a more reasonable and evidence-based approach to recreational drugs, harm minimisation and harm reduction will be reached.

Until next time,

Thursday, 5 April 2012

2012 TIAFT Conference

Earlier this year I submitted an abstract to the chairperson of the 2012 organising committee of The International Association of Forensic Toxicologists (TIAFT), with the hopes of attending the upcoming conference in Hamamatsu, Japan.

Logo for the conference I will have the privilege of attending

Back in 2009 I was afforded the opportunity to attend the TIAFT conference in Geneva, Switzerland. It was truly amazing to meet my peers, and to immerse myself in the buzzing atmosphere of toxicologists sharing their latest research, curious cases and other bits and pieces of fascinating information.

At any rate, I received word today that I will be attending the 50th annual meeting of The International Association of Forensic Toxicologists, and will be presenting a poster at this conference. The abstract I submitted was titled "Further study of the detection of oxidation products of 11-nor-9-carboxy THC (THC-COOH) following urinary adulteration", and will discuss the effects of different oxidising adulterants on the detection of a key secondary metabolite of delta-9-tetrahydrocannibinol (THC) in urine. I really haven't mentioned this research prior to this post, so at some point in the future I shall provide a quick intro into what I am currently researching.

In the coming weeks I will provide a preview of my poster. More importantly, I need to finalise my research so I have a poster to present!

The coming weeks shall be busy indeed.

With kindest regards,