Life Span: The World’s Longest Cohort Studies

This post is inspired by my recent visit to Hiroshima in Japan. Whilst there, I had the chance to visit the Peace Park and Peace Museum. Unfortunately, the latter was under refurbishment at the time, and therefore only half of it was open. The museum did, however, provide incredibly valuable and poignant insight into the effects of the bomb on the citizens of the city. When we visited, it seemed that the exhibits focused only on the detonation and aftermath, and did not encompass the context behind the bombing at all. Presumably, this will be addressed by the renovations.

Little Boy

On the 6th of August, 1945, at 08.15 AM a “Little Boy” atomic bomb was dropped above Hiroshima. It was detonated 580 m above the city, directly above Shima Surgical Clinic. Almost 150,ooo people in total were killed or injured by the bomb.

Hiroshima-peace2

Sadako Sasaki was two years old when the atomic bomb struck 2 km from her home. She was seemingly uninjured by the blast or aftermath. However, at the age of 11, she developed cancerous swellings around her glands. These swellings led to a diagnosis of acute malignant lymph gland leukemia.

There is a Japanese myth that promises a wish to anyone who makes 1,000 origami cranes. By the end of August 1955, Sadako had made more than 1,000 cranes, wishing that she could survive her cancer. By the end of October, she had died. Sadoko’s death led to the building of a memorial for all children who had died from the effects of the bomb.

Long-term Radiation Effects

Sadoko’s story led to further research interest into the long-term effects of radiation. Because people were exposed to the radiation in different forms, the effects manifested in different ways. The long term effects of the atomic bomb included blood disorders such as anemia, cataracts, tumours and keloid scarring around healed burns. As these long term effects were not previously explored, it was not possible to predict them.

crane-1403798There are several kinds of radiation. Alpha and beta radiation do not have high penetrating power – that is, when they reach the skin, they cannot pass through and therefore do not affect the internal vital organs. These kinds of radiation cause skin effects such as burns, or can have wider effects if ingested as contaminated water or food. Gamma and neutron radiation have a high penetrating power, and therefore pass through the skin. Because of this, full body exposure to gamma radiation leads to the symptoms of radiation sickness (nausea and vomiting, falling blood counts, infection).

As the effects of radiation were not widely known, it is likely that many of the aftereffects of the bomb were caused by contamination of the water supply or exposure to “black rain”. These symptoms in particular are associated with radiation sickness due to the internal effects of radiation. Radiation damages DNA and other molecular machinery within the cell. This means that the symptoms are linked to newly synthesized cells, and they manifest most quickly in rapidly-dividing tissues (hair, blood, skin).

The Study

This bomb was the first of its kind to be used in warfare, and no one could fully predict the long term consequences for those surviving the initial blast. The Atomic Bomb Casualty Commission (ABCC) was established in order to conduct long term studies of those survivors. This commission later became the Radiation Effects Research Foundation (RERF), and the study findings can all be found on their website.

These studies are incredibly valuable in understanding the different conditions in which radiation exposure plays a part. Through the voluntary cooperation of tens of thousands of survivors, we have learnt that cancers have higher incidence in A-bomb survivors. There was no evidence of an increase in other mortalities than cancer in the group – presumably because cancer is the disease that specifically stems from damage to DNA and other growth/death mechanisms in the cell (which is specifically what radiation causes).

From an academic point of view, the existence of such a long-spanning study is extraordinary, and it has value beyond its “limited” purpose of studying A-bomb victims. If we followed other patient groups for a life span, we could learn so much about both inherited and environmental factors’ roles in any disease.

We could look at the effects of diet on brain cancer. We could look at the effects of exercise on. Previously unstudied connections could potentially be found. And most of all, we would be able to know these things in healthy individuals, not just those suffering from the disease already.

 

References:

  1. Hiroshima Peace Museum website, accessed 30/08/16: http://www.pcf.city.hiroshima.jp/index_e2.html
  2. Sadako Sasaki, accessed 30/08/16: http://www.pcf.city.hiroshima.jp/virtual/VirtualMuseum_e/exhibit_e/exh0107_e/exh01071_e.html 
  3. Atomic Archive website, accessed 30/08/16: http://www.atomicarchive.com/Effects/effects16.shtml
  4. RERF website, accessed 30/08/16: http://www.rerf.jp/library/archives_e/lsstitle.html
  5. Crane photo taken from: http://www.freeimages.com/photo/crane-1403798

“Expanding” our biological universe

 

I recently (well, fairly recently) gave a presentation in my research group on this topic. Both microscopy and polymer synthesis are sciences close to my heart, so I thought it was worth attempting to explain the science to a wider audience. Please do have a look at the paper or Science Mag. article if you’re interested in learning more. My original presentation took a more in-depth look at the science, but I felt this was not appropriate for a blog post.

Microscopy: Biology’s teeny tiny little camera

Microscopy is a hugely valuable technique in many fields, not least biology. Using microscopy, we have access to high-quality images of structures we could not see by eye, and this allows us to visualise the workings of organisms, cells and even sub-cellular processes.

Microscopy has led to so many key discoveries such as the cell, which was discovered by Hooke using an optical microscope, and it has contributed to and even won Nobel Prizes (such as in super-resolved fluorescence microscopy in 2014).

The issue with optical microscopy

The oldest form of microscope is the optical microscope. These are microscopes using a complex series of lenses to magnify an image. And the higher resolution optical microscopes are termed confocal microscopes. These are able to takes images through z-planes (they take “stacks” of 2D images and show them to the user as a 3D image) and videos of subcellular structures.

microscope-1-1619245

This is where it gets a little complex (apologies). See, there is a problem with typical optical microscopes. Their resolution (that is, the quality of the images, and their ability to zoom in further) is limited by diffraction. Visible light passing through the microscope’s aperture (the hole where light passes through) undergoes diffraction, and this means that two objects separated on a 2D surface (laterally) less than approximately half the wavelength of light used to image the specimen cannot be observed.

SO how do we surpass this limit? Having higher resolutions for our images is ever more important as we learn more about how our cells work. Neurons (brain cells) are notoriously small, for example. Non-optical microscopy techniques are tricky to implement with living tissue as they can damage it. There are, however, expensive “superresolution” microscopes that can break this “diffraction limit”. I’m now going to show you a technique that bypasses the expense and the damage to cells published in the Journal Science.

The solution: “Expansion Microscopy”

An entirely alternative solution to the above issue is to expand up the living tissue to be able to visualise it with a lower-powered microscope. In the Science paper, the researchers infused starting materials for the preparation of a polymer directly into the tissue. They then added a crosslinker to allow the formation of a web of polymer, and chemicals to initiate the formation of the polymer in the tissue. Infusing water into the polymer web (termed dialysis) encouraged it to swell, in the same way that nappies swell when absorbing moisture.

 

pack-of-diapers-1419591

 

Using typical techniques for labelling their samples (confocal microscopy requires fluorescent dyes to visualise specimens), the researchers found their samples to be undistorted, and 4.5 times larger than the original tissue. In this way, the technique showed the ability to visualise samples with the same resolution as superresolution microscopes!

This sort of lateral thinking is a wonderful thing in modern science, as much of the research we do these days is based on what is funded by industry. Keep it coming, scientists!

A note from the author: As my posts sometimes touch on emotive subjects, comments are disabled after 14 days. This is because, at this stage, I feel that ongoing discussions tend to stagnate.

 

 

References:

Science Mag. article

  1. Chen, F., Tillberg, P. W. and Boyden, E. S. (2015) Expansion microscopy. Science Translational Medicine. 346, 6221, 543-548.

Image of diapers was taken from freeimages.com

Five shorter (political) stories: 2

 

The UK is a worrying place to live at the moment, with soothsayers preaching about economic, social and environmental collapse at every street corner (or posting about it on Facebook, at least). This makes it a perfect time to post a few stories about factors leading to political persuasion! In science we trust.

Research by various political scientists has suggested that around half of the variation in political preference is heritable (that is, determined by our genetic makeup). In this post, I’ll be talking about non-heritable (that is, social and lifestyle) factors that affect political persuasion.

Birth order

It may well affect political persuasion. There have been various studies suggesting the impact of birth order, including one in which parents’ social persuasion was not linked. Though it is difficult to ascertain why, it has been suggested that this is due to the “dominance hierarchy in the sibling relationship”. It is suggested that being the first born fosters a sense of privilege that leads the offspring to swing towards favouring the “political status quo”.

Siblings and stereotypes

Men raised with sisters tended to be more conservative according to a recent study. This has been proposed to be related to the attitudes related to gender roles instilled from a young age. Boys with sisters will see their sisters encouraged to engage in household chores and more “girly” pastimes (toys are still very gender segregated to this present day, though attitudes seem to be changing gradually). This early gender stereotyping may translate into more stereotyped roles, again maintaining the status quo, in later life.

Conversely, growing up with a sister had no effect on young girls. In addition, the study has suggested that the effect decreases as the young men grow up. Unfortunately (though not related to this story), the data did show the persistence of gender stereotypes for longer.

Personality profiling

A study has suggested that political persuasion can be predicted as a function of 5 personality traits: Openness, Conscientiousness, Emotional Stability, Extraversion and Agreeableness.

Openness and Conscientiousness were found to be the best predictors, with more of the former correlating to conservatism and more of the latter correlating with more liberal attitudes. The other traits varied more, though Emotional Stability and Extraversion had moderate links to social conservatism but more effect on economic persuasion. Agreeableness, conversely, was related to social conservatism by economic liberalism.

These data in particular suggested that politicians with certain values could have predictable views on an array of policy domains, which is supported by the relative cohesion within a political party relative to beyond.

Oxytocin: the “moral molecule”?

Oxytocin plays a role in social interaction, particularly during sexual reproduction and during and after childbirth. It has been shown to be related to the formation of monogamous pair bonds in humans and other species.

Research undertaken in the Center for Neuroeconomics Studies (CNS) in the US investigated the role of oxytocin in political persuasion. Synthetic oxytocin (or placebo) was administered to volunteers (not females due to its affect on the menstrual cycle) and they were asked about their feelings towards various political figures.

Those of a Democratic persuasion showed more warmth towards their opponents with than without oxytocin, whilst it had no effect on Republicans. This data suggested that those who lean more to the left are less fixed in their views and are more affected by their emotional response.

Voting participation and stress

Though not related to political persuasion, another hormone may have an affect on voter turnout.

A small study explored how cortisol (often dubbed “the stress hormone”) may have an effect on voting activity. Lower cortisol levels in the afternoon were associated with increased voting frequency, but not with non-voting political activity (such as campaining). Baseline cortisol levels predicted behaviour that was not affected by demographics.

Cortisol is a hormone that can also predict participating in social interactions. The paper’s authors note that, as political activity is a stressful undertaking, it makes sense that those with lower stress thresholds might avoid engaging.

The other factor most highly affecting voting turnout was age, with older people voting more often. This study suggested that hormone levels, as well as demographics, should be taken into consideration, however.

 

One thing to note is that much of this research is that it is based primarily on surveys conducted where participants self-report. Although participants have no reason to lie in such studies, there is always the chance. But data on these larger scales is likely to be fairly indicative, and statistics do not lie (most of the time).

 

A note from the author: As I sometimes write on emotive subjects, comments are disabled after 14 days. This is because ongoing discussions tend to stagnate.

Four shorter stories: 1

 

This blog exists as a canvas on which I paint my various musings on science and medicine (and some other things). Years of training does more than just make you able to interpret scientific findings – it makes you acutely aware of how much else there is out there to learn! But sometimes I don’t have enough to say on a particular subject to fill a full article, and that’s okay. This new feature (if it becomes a feature) is where I introduce some short stories that captured my interest, but I haven’t immediately found myself internally linking them to a wider context.

I present to you: the Amazon molly

Let’s start off this serious of short stories in the way we mean to go on, with a story about peculiar mating habits! I believe I read about this phenomenon a while ago in The Scientist magazine, and it stuck with me.

The name of the fish is a reference to the all-female Amazon warriors from Greek mythology for a reason: they reproduce by gynogenesis. This means that only the genetic material from the females of the species is incorporated into their offspring. The Amazon molly mates with a male of a fish from the same genus as itself (Poecilia), but the sperm is required only to initiate embryogenesis (the division of the egg to form a viable embryo).

Though it is interesting, this method of reproduction does limit the ability of the population to be genetically diverse. Two key sources of genetic variability in humans, for example, are from the crossing of chromosomes from two species in sexual reproduction and genetic mutations. The Amazon molly benefits only from the latter, but is able to reproduce faster. A smaller gene pool means that the Amazon molly is less able to adapt to changes in its environment such as disease or climate change.

 

Put Solar on it 

This is a project encouraging people to put solar panels on their homes, commercial building and lands to produce more renewable energy, and it had a national day in the US as a call to action.

Climate change has long been an issue for experts, scientists and politicians, but it’s time to change that. If we want to preserve out own earth we should consider making changes ourselves. Solar panels are now cheaper than ever before, and renewable energy has been proven to be a viable source for all our needs.

 

Wind farms and hurricanes

Another story from the US, and one I heard on Inquiring Minds podcast many moons ago.

Our power industry relies on the conversion of one type of energy being converted to another. Batteries are chemical energy converted to electrical energy, coal/gas are heat energy being converted to electrical energy and wind farms are kinetic energy being converted to electrical energy.

Energy is not just created, it is converted.

It therefore stands that, when we use wind power, we reduce the amount of wind evergy in the atmosphere. A study was carried out wherein it was stipulated that 78,000 turbines could have knocked down Hurricane Katrina and Hurricane Sandy. That’s a lot of free energy, and these turbines could actually save lives.

Does this change what we know about wind power? Well, no, but it might make people listen.

Is it feasible? There is no reason why not.

 

Project Steve

Finally, this is something I heard about on one of my many super fun Science Podcasts. Project Steve is a parody of the tendency of creationist organisations to list those who naysay evolution, amongst many things.

Quite simply, it is a sort of petition wherein scientists called Steve put their name down to support evolution. At the time of writing, 1389 Steves had signed – the website notes that ‘”Steves” are only about 1% of scientists’ to remind us all just how wrong the tradition is to frame certain scientific doctrines as “disputed”.

 

A note from the author: As I sometimes write on emotive subjects, comments are disabled after 14 days. This is because ongoing discussions tend to stagnate.