The potential of youth

cord-blood-aware-fanconi-anaemia1

Previously, I wrote about defying ageing with a focus on miracle creams and lotions. The general consensus is that you cannot stop the ageing process.

However, recently an article popped up in my inbox discussing about how the blood of young mice can rejuvenate older mice. Cue images of horror movies where older people are harvesting young people for their blood!

In reality it is far more complicated than injecting the blood of a young person. We need to know how the young blood factors are acting to ‘rejuvenate’.

The potential of umbilical chord blood

In this particular study the older mice who had received plasma from the umbilical cord blood (UCB) of young mice had more neural connections forming, and showed improved memory and learning compared to control mice.

The researchers found that there was expression of a UCB-specific protein in the hippocampus of the older mice who had received the UCB plasma.

Previously, studies have only been able to demonstrate the ‘rejuvenating’ effects of young blood on older animals through a technique called parabiosis, which is where the circulatory system of two mice are joined (ewww!). Obviously, ethically there would be issues in humans, and in animal research it is a proof-principle technique that is also not overly practical. So knowing that we are able to identify factors in the plasma that can ‘rejuvenate’, is a big win.

UCB can also repair damaged tissue

This same year, another article demonstrated that stem cells isolated from human UCB can prevent kidney failure in rats suffering from acute kidney injury. Currently, human UBC cells are used to treat a range of diseases such as

  • Immune deficiency
  • Leukaemias
  • Blood diseases such as Aplastic and Fanconi Anaemia
  • Metabolic storage diseases
  • Thalassaemia

Final thought

It is undeniable that there are properties of young blood that can ‘defy the ageing process’. In terms of medical research, it seems that these factors will be able to counteract age-related memory loss, and promote repair to damaged organs. Unfortunately, UCB relies on tissues being donated, and has obvious limitations as well as ethical considerations. At the moment these experiments are ‘proof-of-principle’ but pave the way for more UCB-factors to be isolated that may help promote tissue rejuvenation. Think repairing damaged spinal chords!

And, let’s face it, eventually the cosmetic industry will jump on this band wagon to promise ‘age-defying’ treatments!!

Side note

Many hospitals collect human umbilical chord blood. Please consider donating your child’s umbilical chord blood and tissue for medical research or to be used in life-saving treatments.

Australia: www.abmdr.org.au/auscord

US: http://www.parentsguidecordblood.org/en/donate-cord-blood

UK: www.nhsbt.nhs.uk/cordblood

Europe: http://www.eurocord.org/eurocord-registry.php

Advertisements

March for Science

march-for-science

On Saturday April 22nd, I participated in the March for Science. I was expecting, given it was an election weekend in France,  not be many people would march. I was proven wrong, and it was great to see that the march had a good turnout!

Even though the March for Science originated in the US in response to funding cuts for research, the sentiment has been echoed around the world. Researchers everywhere, including Europe and Australia, are facing reduced funding, reduced support and a lack of recognition for the hard work they do.

Being a scientist is not a stable, long term career by any stretch of the imagination. Yet we persist with it out of passion, and out of understanding that society will not move forward, nor will issues such as (gasp) climate change be tackled, if we don’t have researchers. Thus, the need for continued funding.

So maybe each country, and even each researcher had a different reason for marching on the 22nd, but I for one was glad that people were motivated to do it, and for others to see just how many scientists there actually are!

Images of the March for Science (Paris)

18033490_10154992258776210_2207909827476608287_n
The Paris March for Science.
18034268_10154992258711210_4735695959752289575_n
“Breaking News: Science is more ffective than magic (p<0.05)”.
18110477_1328718167166014_2135135030_n
This may have been my favourite! “Sticking your head in the sand is not a solution to Global Warming…Your ass will still get hot!!”
18073413_1328717787166052_476544120_n
“Effect size, not hand size, matters!”

Final Thought

The images shown are from the March for Science in Paris. Thanks to Rebecca Whelan and Rachel Macmaster for the photos.

The myth of the tissue-destroying white-tailed spider

642x361_spider_bites_jumping_spider

Warning: if you do not like spiders, or are squeamish, maybe don’t read this post!

When I was at university, I found a red bump on my elbow that progressed to an actual hole. Many doctor’s visits and anti-inflammatory steroid injections later, I had an impressive scar and perhaps, an impressive story.

A persistent myth

My doctor told me that the hole was the result of a white-tailed spider (Lampona cylindrata and Lampona murina) bite, which causes tissue necrosis. Anyone in Australia has heard about people being bitten by a white-tailed spider and ending up requiring multiple skin grafts, or in the worse case scenario, amputation! In actual fact, spider bite-induced necrosis (necrotic arachnidism) is linked to only one spider, the Brown recluse (Loxosceles reclusa), which is found in the southcentral and southeastern areas of the United States. A compound found in the spider venom creates an acute immune response that results in inflammation-driven tissue destruction.

The link between the white-tailed spider and tissue necrosis is in fact an urban legend that has persisted since the 1980s.

So if the white-tailed spider doesn’t actually cause tissue necrosis, how did I get a hole in my elbow?

The jury is still out

The theories put forward focus on mycobacterium ulcerans infection at the bite sites resulting in an ulcer, or Staphylococcus aureus infection resulting in cellulitis (bacterial skin infection).

It is unlikely that the majority of the cases are the result of a M. ulcerans infection. Firstly, this type of infection is predominantly localised to tropical areas, and is a highly contagious infection. Secondly, studies have shown that the white-tailed spider venom does not carry this bacterium.

The second theory, that the tissue necrosis is from S. aureus infection resulting in cellulitis, is more likely. I couldn’t find a straightforward answer, but it seems that most researchers and clinicians feel that the S. aureus infection occurs from entering at the site of broken skin, i.e. a bite site that someone has scratched.

Final thought

So, despite a lack of evidence linking the white-tailed spider to necrotic arachnidism, the myth persists. I mean, what is going to have viewers glued to their TV or clicking on links:

“I lost my leg to a spider bite!” or, “I scratched a spider bite and now I have a bacterial infection!”

??

Tip: don’t enter tissue ulcer into Google images if you are of a weak constitution…!

Sources

This post was inspired by a recent post in Australian Geographic.

https://www.researchgate.net/profile/Scott_Weinstein2/publication/263096757_A_phoenix_of_clinical_toxinology_White-tailed_spider_Lampona_spp_bites_A_case_report_and_review_of_medical_significance/links/546d38d50cf2a7492c55b3df/A-phoenix-of-clinical-toxinology-White-tailed-spider-Lampona-spp-bites-A-case-report-and-review-of-medical-significance.pdf

http://www.ijam-web.org/article.asp?issn=2455-5568;year=2016;volume=2;issue=2;spage=256;epage=259;aulast=Fegley

https://www.researchgate.net/profile/Maria_Lima4/publication/302556178_Phoneutria_nigriventer_Venom_and_Toxins_A_Review/links/5785002008ae36ad40a4b43d.pdf#page=45

http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0002770

https://www.mja.com.au/system/files/issues/186_02_150107/joh10634_fm.pdf

Disclaimer: the image used in this post is of the common ‘jumping spider’ and is not a white-tailed spider.

All watched over by machines of loving grace

moss-cloche-closeup

I recently saw a documentary at the Palais de Tokyo as part of their exhibition entitled “All watched over by machines of loving grace.” The documentary, by BBC journalist Adam Curtis, was a fascinating insight into systems theory, cybernetics and ecology.

So of course, I took to the trusty scholarly search engines to find out more.

A (vicious) circle

Early scholars of the movement described nature as an electrical circuit, with amplifiers and dampeners of the natural order. In terms of ecology, systems theory described nature as a self-governing machine that responded to changes in the environment and adjusted to maintain a natural balance. In essence, an ordered cycle of life.

feedback-1
A systems theory cycle

This is called a feedback loop, i.e there is a cause and an effect. Following on from this, there can be another factor that then influences the original input.

feedback-3
Feedback loop

Cybernetics

No, I’m not talking about robots!

Cybernetics is at the heart of systems theory, describing nature as a system that can be controlled and managed. Cybernetics considers nature in the bigger picture, looking at the response of the environment to changes.

Cybernetics introduced the concept of ‘negative feedback’, where in order to maintain equilibrium, where the output result that feeds back into the network is out of equilibrium, and is reduced to maintain the steady state.

feedback-2
Negative feedback loop

Earth as a spaceship

Cybernetics spawned the early environmental movement in the 1970s. This was based on the modelling of the ecological feedback loops. Scholars and activists realised that if a steady-state of ecological systems could not be maintained, irreversible damage or a catastrophe would occur.

This produced the idea of the earth as a spaceship. A self-contained object that required all systems to exist and work in harmony in order to maintain a sustainable environment within the ‘spaceship’. If not, water, air, or food would be compromised. In fact, cybernetics also contributed to the development of the Doomsday Clock. This is a metaphorical countdown to the end of the world based on the (dis)equilibrium of the population and our environment.

It’s not just science fiction

Systems theory feedback loops are used in everything from psychology (understanding people’s responses to the environment around them), to machine learning and computers and, to the development of the internet.

Final Thought

The most fascinating focus of the documentary was the realisation that man’s reliance on machines in order to ‘improve’ our quality of life as well as increase productivity in industry, has destroyed the idea of an ecological cybernetic system. The early theorists failed to anticipate that the negative feedback loop would not adjust to a rapidly changing human population, one that was at disequilibrium with its environment. This can be seen in the rapid extinction of animal and plant species, as well as the wealth of some countries versus the absolute poverty of their neighbours.

It really was such an interesting documentary, and I urge you all to watch it (link included in first section).

Sources

Bernard C. Patten and Eugene P. Odum. The American Naturalist, Vol. 118, No. 6 (Dec., 1981), pp. 886-895

http://www.its.dept.uncg.edu/hdf/facultystaff/Tudge/Bronfenbrenner%201995.pdf

http://maft.dept.uncg.edu/hdf/facultystaff/Tudge/Bronfenbrenner%201977.pdf

https://staff.washington.edu/jhannah/geog270aut07/readings/population/Ehrlich%20-%20Population%20Bomb%20Ch1.pdf

 

 

The Communication Series

communicate_employees

It might be surprising to know that communication, that is, how we communicate, what we say (even when we aren’t saying it) and how the communication is used, is quite a complicated field of study. In the next few posts that I am calling “The Communication Series”, I discuss the theories and analyses of communication.

Communication theories attempt to describe and give purpose to the way that the communication processes occur and have advanced, as well as attempting to suggest ways to improve communication by highlighting limitations.

These theories are generally applied to organisations where there are clear structural and power differences and communication can either enhance or impair an organisations success.

What you talkin’ about?

At the heart of communication is discourse, which encompasses the information and knowledge being relayed. Having said that, communication is not just a means in which information is moved between individuals, but it is a way of reinforcing and establishing ideas, ethics, structure, ethos as well as output and productivity.

Who you talkin’ to?

If we take a business as an example, effective communication is critical for its interaction with employees/team members as well as with the environment outside of the organisation. The communication is therefore essential to its success.

Continuing with the ‘business’ scenario, the communication can be between peers on the same hierarchal level, managers to employees, or boards of directors to managers. Outside of the business, it can be by customer feedback, profit, the ability of the organisation to expand, marketing/public image, or how the organisation compares with others within the same industry/field.

What did you just say?

What is important to remember is that communication is not just the act of saying words, but can also be from responding to stimuli or by the interpretation of facial expressions and behaviour. And let us not forget that it can also be electronically delivered, such as on a blog, for example….

Ch-ch-ch-ch-Changes

If how and what we say can change, as well as the interpretation of the message, it demonstrates that communication is an ongoing, changing process. For effective communication to occur, incorporating the varying nature of communication is crucial. If we go back to the business scenario, how an organisation understands these changes and implements them to create new environments can define the organisation, i.e. the means and processes by which individuals within the organisation communicate in order to work together.

The many theory phenomena

Not every organisation is structured similarly, meaning the ways in which they communicate are vastly different. For example, how does communication work in organisations that are hierarchical versus organisations that are collaborative? How do the organisations tackle social and cultural changes, and how do they use communication to incorporate these changes? Hence, just as there are different styles of communication and organisational structures, there are also different theories that can be applied to how communication works within these organisations.

The three main theories are functional, centred and emerging.

“The Communication Series Theories”

The functional theory can be described as performance based, focusing on how messages move through an organisation. It focuses on how rules and regulations resulting in output and yield, shape the communication. This theory focuses on structure, and does not apply well to changing methods of communication and culture.

The centred (or meaning-centred) approach asks how symbolism, stories and emotions are used to construct social structures and personal relationships. This approach encourages incorporating change and the ever-changing nature of communication.

Emerging communication theory focuses on newer and more critical theories that are being applied to communication. In the following posts I will discuss two to of these newer theories – critical and post-modernism.

Sources

All sources used throught “The Communication Series” will be placed in the final post. However if you are genuinely interested in a source, send me a message!

A post to remember?

p049z11y

When I was young, I used to ask my mum what it was like when she was a child. Her response of ‘I don’t remember it was so long ago’ always astounded me. I was convinced that I would remember everything! Flash forward, and while I have some strong, distinct memories from my childhood, much of it is gone, just like my mum’s. So what are memories? How are they formed and stored and, how do we lose them?

I remember

Memory is the retention of knowledge. Both neuroscientists and physiologists agree that this is a broad term covering different aspects of knowledge accumulation. In a general sense, this covers whether the knowledge is purely emotional, linked to a time and place, or if it is related to environmental stimuli.

Much of what has been gleaned about memory comes from medical conditions in which people cannot retain memory or demonstrate memory loss. For example, in individuals with Alzheimer’s, it has been demonstrated that the hippocampus region of the brain is necessary to memory formation. It has been found that there are certain proteins in the hippocampus that are targeted by beta-amyloid peptides (small proteins that are found in the brain tissue of individuals with Alzheimer’s) that result in memory loss. Restoring the levels of these proteins in mouse models of Alzheimer’s restores the ability to learn and remember.

The hippocampus has been shown to be integral in the formation of episodic memories. An episodic memory is one which recall is via the stimuli of a place and/or time. New episodic memories can use the ‘parameters’ of a previous episodic memory and retrieval can involve thoughts and emotions of other memories. This can be why one place or emotion can trigger a multitude of memories! This has been shown experimentally from imaging of the brain. The area of the brain involved in performing an activity associated with a particular place was the same area used to conduct recall of an episodic memory associated with the same location. It has also been demonstrated that stimulation of the hippocampus produces a similar neural response to novel stimuli.

I will remember for ever and ever

So how is it that we fail to remember a conversation we had yesterday but can recall the phone number of the first house we ever lived in?

This comes down to short-term memory versus long-term memory.

Short-term memory is often also referred to as working memory (WM), and is retained for approximately 15-30 seconds. These memories are in a readily available state and usually apply to a task being performed. Repetition of the task or repeated exposure to the stimuli shunts the memory to long-term recall.

A process termed long term potentiation (LTP), is the persistent strengthening of neural cell structures called synapses in response to recent repeated activity. These synapses also exhibit plasticity, a term for the ability of synapses to weaken or strengthen in response to increases or decreases in activity. Memories that ‘fade’ are a phenomenon that neuroscientists call memory extinctionwhere a conditioned response is forgotten as older memories are replaced with new experiences.

Physiologists have demonstrated that dopamine plays a role in memory formation, in particular short-term memory. Neurons in the hippocampus that are receptive to dopamine will respond rapidly to novel stimuli, but as the stimuli become more familiar, the cells no longer respond. And, interfering with dopamine can block LTP, while making cells more receptive to dopamine enhances LTP.

As it is known that there are also learned responses based on both reward and behaviour, how are memory systems (i.e. WM vs LTP vs reward-based memory formation) recruited?

It is the general consensus that in the case of dopamine and LTP, it is only for stimuli that will be behaviourally advantageous. For other memory systems, recruitment of a system is based on the anticipated demands of a memory and can involve a feedback mechanism that predicts the outcome from interaction with stimuli.

This is where it can become a little confusing! The different parts of the brain control different memory systems. As discussed, the hippocampus is involved in LTP while the prefrontal cortex, for example, is involved in the maintenance and manipulation of WM.

One study demonstrated that if an individual was distracted or had increased delay between memory recall during a task that required WM, LTP increased with a decline in WM accuracy. The authors concluded that the anticipation of increased difficulty in completing or performing WM tasks led to a shift away from WM in order to preserve high-level performance.

It’s in the genes?

Very little is known about the biology of memory. Studies into Alzheimer’s have yielded much of the information about proteins that are crucial to retaining memories.

Neuroscientists combine the memory tests with investigating what is going on at the genomic level, and have found that different genes are activated along with differences in protein production. This can depend on the memory system. However, it is increasingly obvious that epigenetics plays a very important role. Modifications to DNA and proteins that change their activity without changing the genetic or protein code are rapid and occur in response to environmental stimuli. Furthermore, these changes are plastic, which as discussed, is important to memory formation and retention. This is an exciting area of research, with much more to come!

It has been demonstrated that diet can affect memory. In particular, a high fat diet (HFD) can result in poor memory retention, and in animal studies, disrupts learning and performance. It is known that a HFD results in insulin resistance of cells in the hippocampus that impairs insulin signalling.

One study observed that mice on a HFD exhibited reduced exploration time of a novel object, and when re-introduced to the object, spent more time investigating the new object compared to control diet mice. These results indicated that both WM and LTP were affected by the HFD. When the diets were changed, the effects on memory were reversed. Food for thought?!

 Liar, liar pants on fire!

The demonstrated plasticity of memory formation and recall can also result in false memories. A false memory is the recall of experiencing something that wasn’t actually experienced.

There are two types of false memories, misinformation-formed and spontaneous false memory formation.

Studies have demonstrated that children seem particularly susceptible to spontaneous false memory formation, while in adults sleep deprivation can be a cause. If a person is sleep-deprived at the time of being presented with the stimuli and later provided with misinformation, their recall of the events can be different to what occurred.

This has also been demonstrated in individuals who exhibit ‘total recall’. These people have an ability to recall memories in rich detail unaided by mnemonics or memory aids. Memory recall from these individuals can also be corrupted by misinformation or misleading suggestions.

I forget

With all that we have learned about memory formation and retention, what about age-related memory loss?

Age-related memory loss is associated with a reduction in the activity of genes involved in plasticity, degradation or loss of neurons, and decreased plasticity. The hippocampus in particular appears to exhibit age-related decay that can lead to a loss of autobiographical recall.

However, not all memory systems are affected by age. One study showed that there were not age-related differences in the ability to learn configural tasks, but that there were delayed response times i.e. older adults repeated the tasks more slowly. The older adults did show a deficit in recalling tasks associated with newly learned episodic memories, with higher false memory recall. This was further confounded if several cues could initiate the retrieval of a memory.

However, all is not lost. A recent study demonstrated that the injection of blood from young mice could counteract ageing at the molecular, structural, functional and cognitive levels in the hippocampus of aged mice!

While the authors observed these changes, they had no data to explain why and how the changes occurred. They cited that it was possibly ‘pro-youthful’ factors that promote regeneration of decaying tissue or affect the activity of ‘pro-ageing’ factors. Current literature suggests that stem cells in the young mouse blood may play a role.

Stress is also linked to poor memory retention and recall, as is a lack of sleep.

Final thought

While it appears much is known about memory, it is acknowledged that there is still a long way to go to understand the brain and memories. Unfortunately, progress is generally made by understanding how something has gone wrong.

Sources

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3917549/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4669102/

http://www.sciencedirect.com/science/article/pii/S0896627305003971

https://www.researchgate.net/profile/Michael_T_Rubens/publication/271534628_Expectations_of_Task_Demands_Dissociate_Working_Memory_and_Long-Term_Memory_Systems/links/551452290cf2eda0df30c824.pdf

http://neurosciencenews.com/neurogenetics-memory-extinction-ptsd-413/

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0163883

https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-016-0261-6

https://escholarship.org/uc/item/50h3w3pn#page-1

http://www.pnas.org/content/110/52/20947.full

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137260#sec020

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5067022/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4224436/

Dose matters

x-rays_banner

Do you ever think about how much radiation you receive when you fly long-distance, have a dental X-ray or undergo a CT scan?

Much of what we know about the risks arising from radiation exposure come from studies on the Hiroshima and Nagasaki bombings during WWII. Despite only having data for high doses, it was concluded that all doses, no matter how small, were harmful and that the risk of cancer increases exponentially with dose. This is termed the linear no-threshold model (LNT). LNT is in contrast with what radiation biologists have demonstrated experimentally for more than two decades, that below a certain dose, where the LNT is extrapolated, risk is reduced and often the low dose appears to have a ‘protective effect’. This has been termed the radioadaptive response.

ionizingvsnon-ionizing

Radiation can be ionising (e.g. X-rays) or non-ionising (e.g.. microwaves). Non-ionising radiation does not have enough energy to displace electrons and therefore cannot cause damage to cells and other molecules such as DNA.

Why is this important? Understanding safe low dose exposure is an increasing concern where legislation and safe work practices are concerned. Increasing availability to the masses of medical imaging devices such as CT scans or dental X-rays, airport whole body scanners, increased air travel as well exposure to background radiation in mines means that greater understanding of safe radiation exposures is required.

So many factors can confound the determination of safe levels. At the simplest level it can be whether the exposure is single or repeated, whether it is whole body or targeted at an individual organ (important as different organs display different radiation sensitivities). And then, there is the agreement on what a low dose of radiation is. Even in research laboratories this can differ. Further adding to this is the consideration of natural background radiation arising from naturally emitting materials such as granite, or radon carried in the air. Even bananas are radioactive! Did you know there are some countries in the world where the natural background radiation is as high as receiving a CT scan or a dental X-ray, without increased rates of cancer or other radiation-induced problems?!

My own PhD lab has demonstrated that a low dose of X-rays can protect against DNA damage induced by a high dose, when given before or after the high dose exposure, while others have demonstrated that the incidence of tumours in radiation-sensitive mice can be reduced if the mice are given a low dose first.

Recently, a study into the deaths of nuclear industry-workers in France dating back 60 years reported that there was an increased, proportional risk in leukaemia. But only for extremely low doses. These individuals were exposed to doses just a little higher than background radiation doses, but accumulative. The only problem with studies like this, and it was pointed out by the authors, is that the risk was calculated based on mathematical model and the accumulated radiation doses cannot be directly linked to the deaths.

Based on increasing evidence that the LNT model cannot be used to justify exposures, there are many who say that a new model for radiation exposure and risk needs to be proposed. Public understanding of radiation, and what constitutes damaging radiation, also need to be addressed by scientists and legislators.

The take home message should be that radiation is harmful, but the question is still “at what dose does risk become neglible, if at all?”

Sources

http://www.nature.com/news/researchers-pin-down-risks-of-low-dose-radiation-1.17876

http://www.ansto.gov.au/NuclearFacts/AboutNuclearScience/NaturalBackgroundRadiation/index.htm

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4030667/

http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/34/086/34086353.pdf

http://atomicinsights.com/science-falsified-no-safe-dose-hypothesis-radiation-now/

Hooker et al. Radiation research 162.4 (2004): 447-452.
Dayet al. Radiation research 167.6 (2007): 682-692.
Mitchel et al. Radiation research 159.3 (2003): 320-327.