Above is an electron micrograph of a cannabis sativa leaf.
Disclaimer: When conducting and even reading scientific research, it’s important to do so removed of pre-conceived social and political biases - take the science at face value.
Research on the psychoactive drug, cannabis, or marijuana, has been ablaze for some time. An article published by Robert Melamedeon the online Harm Reduction Journal draws the distinction between tobacco smoke (that contains the highly addictive compound, nicotine), and cannabis smoke (which contains the psychoactive, THC). At this point in time, it’s medically established that marijuana, even when smoked, has less severe adverse effects on the human body than tobacco. Yet the question remains - what are the degree of the detrimental effects that cannabis does have, and are there any medically beneficial effects?
Some research points to cannabis killing a variety of cancer types, including lung, breast and prostate, leukemia, lymphoma, skin, and glioma cancers. At the same time, however, a German study found that low THC doses encouraged lung cancer in in-vitro cells. Seemingly contradicting results, no? Just keep in mind that while nicotine and THC are chemically similar, their actual receptors in the human body vary in cell type distribution, which is what ultimately determines the effects on the human body.
… cannabis typically down-regulates immunologically-generated free radical production by promoting a Th2 immune cytokine profile. Furthermore, THC inhibits the enzyme necessary to activate some of the carcinogens found in smoke. In contrast, tobacco smoke increases the likelihood of carcinogenesis by overcoming normal cellular checkpoint protective mechanisms through the activity of respiratory epithelial cell nicotine receptors. Cannabinoids receptors have not been reported in respiratory epithelial cells (in skin they prevent cancer), and hence the DNA damage checkpoint mechanism should remain intact after prolonged cannabis exposure.
I highly recommend this article, which you can read fully here. It gives great insights into cell biology within a biomedical context.
Image: Courtesy of David Scharf, via The Scientist
Article: Melamede, Robert. “Cannabis and tobacco smoke are not equally carcinogenic.” Harm Reduction Journal, 2005. Web. 10 October 2012.