Neutrophils, DEHP and immune dysfunction

October 21, 2010 at 2:34 pm | Posted in Briefing | Leave a comment

Although classified as a CMR and banned in toys, DEHP is still widely-used in medical devices. DEHP is already believed to pose problems with reproductive health.

This month, we look at mounting evidence that DEHP may also present an immediate threat to neonatal health by potentially compromising normal immune response.

Below is footage of a neutrophil absorbing a bacterium. If neutrophils become activated at the wrong time, they can exacerbate inflammation and increase the risk of developing a range of health problems.


Prins et al. (2010) BPA and Prostate Cancer in Rats

October 16, 2010 at 11:13 am | Posted in Analysis | 2 Comments

 

Prostate Cancer

Prostate cancer with Gleeson pattern. (Image: Nephron, Wikimedia Commons.)

 

The Daily Mail (UK) recently covered a new study (Prins et al. 2010) finding that when male rats are exposed prenatally to low doses of BPA, they are more likely when they became adults to develop precancerous PIN lesions in the prostate gland.

The study is important for two other reasons. Firstly, the levels in the rats are comparable to the levels generally seen in people today.

Secondly, Prins’ team experimented with different exposure routes, both feeding the rats BPA orally, and dosing them with subcutaneous injections. Both routes produced the same PIN lesion effect.

This is important because for the purposes of determining BPA’s safety, human dosing is assumed to be oral. Experiments based on dosing test animals by injection have therefore been discounted in determining the safe levels of exposure for people.

Finally, in the article a cancer charity is described as “[urging] people not to worry, saying that bisphenol A breaks down much more quickly in the human body than in a rat”. However, a recently published study by Taylor et al. (2010) has found this not to be the case.

Additionally, BPA exposure is more-or-less continuous, found in about 90% of the population at any given time: it doesn’t matter how quickly BPA breaks down if you are ingesting it as quickly as you clear it.

The charity goes on to say that a healthy diet is the most important means for men to prevent prostate cancer and that BPA is considered safe by the food industry. Commenting in this way on Prins et al. is arguable on two points:

  1. Diet is an important risk factor for prostate cancer, but Prins at al. are looking at how neonatal exposure changes adult risk of cancer, so discussion of diet misses the point;
  2. Finally, and rather obviously, BPA is considered safe by many (though not all) players in the food industry… but the same could equally be said about cigarettes and the tobacco industry.

Related Links

Progress in Children’s Environmental Health

October 6, 2010 at 12:35 pm | Posted in Uncategorized | Leave a comment

An editorial in this month’s EHP describes progress in children’s environmental health issues, charting changes in perception and challenges faced in reintroducing concepts which used to be central to medicine and health.

One particularly interesting point is the observation that health professionals have become isolated from the professionals who implement their recommendations: buildings go up, towns are planned, waste management schemes are introduced, but all too often health is left out of the picture.

Why has it been so difficult to move from knowing to doing? First, many of the decisions affecting children are made not by those in the health sector, but by our professional colleagues in the agriculture, education, energy, housing, mining, and transportation sectors.

Just as “men are from Mars and women are from Venus,” it seems as if professionals in each of these sectors are from different planets. Although we may speak the same language, we rarely have more than a cursory understanding of the forces that shape one another’s decisions and other considerations.

Because the CEH movement has focused on educating the health community, few efforts have been made to establish relationships with other economic sectors. To use a developmental analogy, we are still involved primarily in “parallel play” rather than team sports. Professionals in the health sciences may work alongside professionals in other sectors, but we are absorbed in our own activities and usually have little interaction outside them.

Instead of sitting at the table with urban planners, housing specialists, and energy experts when health professionals are planning an approach to a child health problem such as asthma, we usually move forward to design a study, implement it, analyze the results, and then present it as a fait accompli to our colleagues in other economic sectors, and hope that they will find it useful.

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