HIV baby cure: One year on

HIV1 150x150 HIV baby cure: One year onWith over 30 million sufferers worldwide, HIV remains the world’s leading infectious killer. The human immunodeficiency virus attacks the immune system, leaving it unable to fight infections, resulting in AIDS. Improving HIV care is one of the top 10 global health priorities. Therefore, when research published last year suggested a baby had been “cured” of HIV; tabloids quickly began to speculate, with some implying the elusive cure may be closer than we imagined. One year on, with similar cases set to be presented at AIDS 2014, the leading international conference on AIDS, what is the significance of this major breakthrough in terms of tackling the large-scale HIV pandemic?

“Absence of Detectable HIV-1 Viremia after Treatment Cessation in an Infant”

HIV2 300x200 HIV baby cure: One year onIn 2010, a baby was born prematurely to a mother whose HIV was only discovered during delivery.   With no prenatal care, and therefore a high risk of exposure to the virus, the gutsy call was made to begin aggressive treatment with a combination of three antiretroviral drugs at just 30 hours old.  Infection was confirmed soon after and the child remained receiving therapy.

Surprisingly, within days the level of HIV had rapidly diminished and within a month was non-detectable. However, the successful therapy was unexpectedly ceased after 18 months as the mother stopped taking the child to scheduled appointments. When the child was finally examined again, at 23 months, she remained free from infection despite not being on HIV medication. At the time of the paper the child continued to be in remission, gaining the title “the baby cured of HIV”.

Impact on cases involving babies born with HIV

HIV3 HIV baby cure: One year onThe doctors quickly emphasised the therapy proposed was a “functional cure”. With the child recently beginning to shown early signs of infection, it appears the treatment silenced the virus for a substantial period of time rather than eliminating it. In reality, cases involving mother-to-baby transmission are rare. Standard HIV pre-natal treatment can lower the risk to 2%.  Therefore in areas where there are a significantly higher number of cases, such as Sub-Saharan Africa, the main factor is the sub-standard levels of health care rather than the need for new treatment.

Is a new, miraculous treatment now available?

HIV4 HIV baby cure: One year onThe therapy itself wasn’t novel as it used readily available antiretroviral drugs; the “novel” aspect of the therapy was the early approach. This is already known to be advantageous as early aggressive treatment is thought to prevent viral reservoirs forming. HIV reservoirs are what hide the virus, making it resistant to the both the immune system and medication, and form within hours of infection.

Can adults now be cured of HIV?

There has been speculation that the immune response of a newborn is more suited to cope with HIV than an adults. Not only are babies immune systems immature, resulting in a milder reaction to the virus, but they lack the memory “defender” cells that are the target of the dangerous viral reservoirs. However, last year several adults were reported to have undergone a similar “functional cure”. Having undergone early antiretroviral treatment, 14 out of 70 patients remained virus free for at least 3 years, following cessation of therapy. This suggests that 5%-15% of HIV patients could eradicate the virus through early treatment.

Early treatment plans would not benefit current sufferers but could help tackle new cases. While treating the virus as soon as possible seems like an obvious idea, it appears it would be difficult to implement. Not only do 1 in 5 sufferers remain unaware they are infected, but the stigma associated with HIV means many people are reluctant to get tested. Therefore, before getting excited over the potential of early treatment regimes, the bigger challenge of identifying the infection promptly needs to be addressed.

The “functional cure” has provided hope and opened new areas for scientists to explore. Importantly, it strengthened the idea that early treatment is vital. However bigger social and development issues, involving improving health care in poorer societies and ensuring early identification, need to be addressed before the findings can be translated into the “HIV cure” that has been widely speculated.

Post by: Claire Wilson

References

Persaud, D., et al., Absence of Detectable HIV-1 Viremia after Treatment Cessation in an Infant. New England Journal of Medicine, 2013. 369(19): p. 1828-1835.

Saez-Cirion, A., et al., Post-Treatment HIV-1 Controllers with a Long-Term Virological Remission after the Interruption of Early Initiated Antiretroviral Therapy ANRS VISCONTI Study. Plos Pathogens, 2013. 9(3).

Posted in Claire Wilson, News in brief | Leave a comment

The decline of the antibiotic – taking medicine back to the dark ages?

Anti biotic 300x211 The decline of the antibiotic   taking medicine back to the dark ages?After being struck down with a particularly nasty chest infection, I initially put off going to see the doctor and instead opted for lots of rest, fluids and self-medication. After suffering at home for a few weeks with no alleviation of my symptoms, I eventually decided enough was enough and went to see the doctor. I was subsequently diagnosed with pneumonia and prescribed antibiotics to treat the infection, after which my  symptoms finally began to ease.

My reluctance to seek medical intervention was due in part to two reasons;

  • My general dislike for going to the doctors
  • Concern over recent news articles discussing the demise of the antibiotic due to over- prescribing.

It is the second of these reasons which seems to be a particular cause for concern.

The evolution of disease-causing bacteria, leading to antibiotic resistance, is a concern which has been high on the scientific agenda for decades. However, the media are only just starting to catch on to the stark reality that faces us. David Cameron has recently taken notice of this impeding issue, referring to the problem as ‘taking us back to the dark ages’. Cameron has called for a review into microbial resistance and has called for drug companies to invest in finding the next generation of antibiotics. But is this too little too late?

If our bodies become infected with foreign bacteria our internal immune system (white blood cells) act swiftly and efficiently to stop the spread of infection – usually before it has the chance cause noticeable symptoms. More often than not, our bodies are able to cope with such an attack without intervention. However, sometimes our bodies become overwhelmed and are unable to cope on their own – this is when we need to seek help from antibiotics.

Antibiotics have been relied on for the last 70 years and are vital in the treatment of bacterial infections (they are useless in the fight against viruses). These drugs work in one of two ways:

  • By interfering with the bacterial cell wall or the contents within – a process which destroys the bacteria (bactericidal).
  • By slowing down the growth of bacteria that can cause illness or disease (bacteriostatic). Thereby, ensuring that the bacteria is no longer able to multiply and infect us.
MRSA 300x286 The decline of the antibiotic   taking medicine back to the dark ages?

MRSA superbug showing resistance to antibiotics as the bacteria (yellow) overwhelm the white blood cells (red).

The development of antibiotics peaked in the 1950’s, after which there was a sharp decline in their development – no new classes of antibiotics have been developed since the ‘80’s! This is perhaps because there is not much money to be made from discovering new forms of antibiotics, so the pharmaceutical industry tend to focus on other, more lucrative, areas of research.

But how exactly does resistance to these drugs occur? When our bodies become infected with bacteria, there is a small chance that some of the bacterial cells show a natural resistance to antibiotics and therefore remain unaffected by the drug. This resistance could be due to a mutation that occurred by chance, or could be as a result of evolution – effectively the bacteria out-smarts the drug. These few remaining resistant bacteria survive, and rapidly reproduce so that the body becomes overwhelmed by this resistant strain. Drug resistance can then be transferred between bacteria through reproduction, physical connections between different cells and also through viruses called bacteriophages.

Resistance 300x278 The decline of the antibiotic   taking medicine back to the dark ages?

The mechanism of antibiotic resistance

Antibiotic resistance is accelerated by over-use in the health-care and farming industries. Which is a growing concern, as many patients fight with doctors to be prescribed antibiotics for all minor ailments without considering the consequences of using them unnecessarily.

Resistance 2 The decline of the antibiotic   taking medicine back to the dark ages?

Bacteria presented with 4 different types of antibiotic. In three cases the bacteria is resistant to the antibiotic and in one case only the drug is sufficient to treat the bacteria.

Antibiotics are also heavily used for intensive farming. With such a demand on farmers to produce lots of cheap meat, animals are housed in cramped conditions where infections are easily spread. Of course to prevent this spread, copious amounts of antibiotics are often used. This overuse facilitates resistance. Resistant bacteria are then able to spread from farm animals to people via our water supplies, which can then spread further from person to person by physical contact, coughing and sneezing.

Now that we know the extent of the issue of antibiotic resistance, what can be done to tackle the problem both in the short and long term? Currently, drug-resistant superbugs such as MRSA and C.difficile cause 5,000 deaths a year in Britain. This has been controlled to some extent by implementing more stringent hygiene procedures in hospitals such as frequent hand washing and anti-bacterial hand scrubs. However, the occurrence of other resistant bacterial strains are on the rise; E.Coli cases have risen by two-thirds over the last few years.

In the short-term, a 5 year Anti-microbial Resistance Strategy has been put in place by the Department of Health which outlines a number of different points that are effective in the fight against antibiotic resistance;

Aim #1 To understand antibiotic resistance: to collect as much information as possible about the mechanisms that bacteria use to become resistant and to understand how the resistance spreads.

Aim #2 To conserve our current antibiotics: by improving hygiene in hospitals and by educating doctors and nurses about the issue of resistance, and encouraging them to only prescribe antibiotics when absolutely necessary.

Aim #3 To encourage the development of new antibiotics: by providing more incentives for pharmaceutical companies to invest in antibiotic development.

In terms of addressing antibiotic resistance in the long-term, several approaches can be taken. Firstly, we need to tackle the issue of over-prescribing. Currently, there are no diagnostic tests that allow doctors to determine whether infections are caused by bacteria or virus. So, developing a test that could determine the basis of aninfection would help doctors give the correct prescription. Secondly, drug companies need to create new classes of drugs to tackle bacterial infections. Thirdly, we can try to reduce the use of antibiotics in farming. Lastly more research needs to be conducted into a new innovative approach to tackling infections which uses viruses to treat bacterial infections.

A combination of over-prescribing and the lack of development of new antibiotics means that these drugs are rapidly becoming less effective in their fight against infections. There is the fear that, in the very near future, these drugs will cease working completely and simple things to treat such as cuts and flu will be likely to make us very ill and even cause deaths.  With no suitable alternatives to antibiotics we could be looking at a very bleak future for medicine.  With all of this in mind it is clear to see that the pharmaceutical and medical industry needs to make huge investments into developing new classes of antibiotics to fight these super-resistant bacteria. Alongside this, doctors need to be sure to prescribe these precious drugs sparingly and patients need to be careful not to rely on them so much for minor ailments.

Post by: Sam Lawrence

Posted in News and Views, Sam Lawrence | Leave a comment

The Science of Star Trek: – The Trouble with Tribbles

This is the first in a series of posts exploring the science of Star Trek, courtesy of our friends at the Scouse Science Alliance. In this first post we delve into the real-life biology of everyone’s favorite purring ball of destruction – the Tribble!

parsons1 The Science of Star Trek:   The Trouble with TribblesThese cute, fluffy, purring balls of joy are considered a mortal enemy of the Klingon Empire (Klingons are a warrior race who love a good battle, and in Kirk’s era they were often the bad guys). They notoriously multiplied uncontrollably on board the USS Enterprise under Captain Kirk in the episode ‘The Trouble with Tribbles’. Starfleet considers them dangerous organisms and forbids them from transport. Despite their purring nature towards humans, the same is not true of Klingons. In fact, Kirk used a Tribble to identify a Klingon in disguise. The Tribble reacted with a screeching noise. Now, how exactly do these fluffy little puffs manage to multiply at such extreme rates? Cleverly, each Tribble is ‘born pregnant’ and if given the smallest morsel of food, will give birth to 10 Tribbles, who in turn will also produce 10 Tribbles. Within hours you have hundreds of Tribbles, clogging up every console, air vent, and food replicator [2].

Is such a creature possible I hear you ask? Well, being a hermaphrodite is nothing new. Snails and plants are examples of this. They possess both male and female reproductive organs, although the female organs of one snail will normally mate with the male organs of another snail, i.e. sexual reproduction. However, in some hermaphrodites self-fertilization can occur [3]. Then there are those species that are able to effectively create clones of themselves via asexual reproduction, such as stick insects. The advantage of asexual reproduction is that it is a relatively quick way to populate an environment, and it does not rely on regular encounters with the opposite sex. It is considered most advantageous in favourable, stable environments. The down side is the inevitable lack of genetic diversity, which would be particularly problematic if conditions became unfavourable. Despite this, some stick insects have been shown to survive for a million years without sexual reproduction, suggesting that this method is genetically sustainable [4].

Therefore, it is very plausible that Tribbles are able to produce offspring in the absence of another Tribble. The only questionable aspect is the sheer speed at which they accomplish this. The shortest gestation period known currently for a mammal on earth is 12 days for the opossum. This animal is a marsupial and whilst it has a very short gestation period, its young are born almost foetal-like and therefore require nursing in the mother’s pouch for an extended period of time before reaching maturity [5]. With regards to Tribbles, not only would their gestation period have to take place in a matter of hours, but the ‘baby’ Tribblewould also have to reach maturity in an equally rapid manner.

If this could actually be achieved, then it would be a huge survival advantage. To be able to maximise breeding potential and minimise the energy intake required tparsons2 The Science of Star Trek:   The Trouble with Tribbleso do so, is the ambition of all species. What’s more, this rapid production of generations would only serve to increase mutation rates, which in some instances can help species adapt. In fact, much of this can be likened to microbes such as viruses and bacteria. Their rapid succession of generations allows them to adapt much more quickly than us, their human hosts. Therefore Tribbles are merely a victim of their own success. All they want is to eat and breed as efficiently as possible, who doesn’t? So in conclusion, Tribbles are quite like microbes, and microbes aren’t so bad. In fact, they can be quite cute and fluffy too!

SSA 150x150 The Science of Star Trek:   The Trouble with TribblesThis post, by author Bryony Parsons, was kindly donated by the Scouse Science Alliance and the original text can be found here.

 

 

References

  1. http://www.edparsons.com/2006/03/google-earth-inspiration-was-star-treks-tricorder/
  2. Okuda, M. and Okuda, D. 1997. The Star Trek Encyclopaedia, a reference guide to the future. Updated and expanded edition. POCKET BOOKS, USA. P 522.
  3. Campbell, N. A. and Reece, J. B. Biology, sixth edition. Pearson Education, Inc, USA. P 975-978.
  4.  http://www.bbc.co.uk/nature/14122050
  5. http://www.opossumsocietyus.org/opossum_reproduction_and_life_cycle.htm
Posted in Uncategorized | Leave a comment

The best laid plans o’mice and researchers: my top 5 chance scientific discoveries.

Most scientists are rarely content until they can say that they have planned for all eventualities. But no matter how hard you try, lab work will often throw you a curve ball, turning up all manner of unexpected curiosities. Yes, it’s true the “best laid plans o’mice and researchers gang aft a gley”*! However, there is no need to despair, for buried in the annals of scientific literature are a number of compelling tales where odd results and downright stupidity have actually lead to some pretty ground-breaking discoveries. So, here are five of my favorite examples of scientific serendipity.

5) The artificial pacemaker:

First pacemaker Siemens Elema 1958 150x150 The best laid plans omice and researchers: my top 5 chance scientific discoveries.

The first implantable pacemaker

The first implantable pacemaker was invented and developed by electrical engineer and prolific inventor Wilson Greatbatch. But this is no ordinary tale of academic prowess. Unfortunate and clumsy scientists can take heart to learn that, despite Greatbatch’s impressive academic repertoire, it was actually a technical mistake which lead him towards this life-saving invention.

In 1956, Greatbatch was working on a device to record heart-rhythms when he accidentally connected an incorrect electrical component (for the geeky this was an ill-fitting resistor). This mistake meant that his device actually emitted electrical activity instead of recording it.  Greatbatch worked on miniaturising and testing his creation and by 1960 the first artificial pacemaker was implanted into a human patient. The recipient, a 77  year old man  went on to live for a further 18 months.

This is a great example of when a technical error actually translated into a ground-breaking discovery. But be careful, 99% of the time such mistakes are still significantly more likely to end in blown fuses and angry screaming than medical breakthroughs!

4) The discovery of penicillin.

Alexander Fleming 300x225 The best laid plans omice and researchers: my top 5 chance scientific discoveries.

Alexander Fleming

No list of accidental scientific discoveries could be complete without the tale of Alexander Fleming’s discovery of penicillin. Fleming, who at the time was described as a careless lab technician (charming), returned from holiday to find that one of his badly tended experiments had grown mould. Although in this instance, his inability to maintain a sterile work environment actually revolutionised modern medicine.

Fleming noticed that the Staphylococcus bacteria  in this particular sample did not grow around the mould. Indeed he noted that the Staphylococcus colonies became transparent and were obviously dying.  The mould was soon identified as a rare strain of Penicillium notatum, which appeared to secrete a compound capable of stopping bacterial growth. In fact Fleming’s mucky lab practices had lead him to stumble upon the first known antibiotic – a discovery which has since changed the course of medicine and allowed for previously life-threatening diseases to be completely curable.

Fleming himself is quoted as saying: “One sometimes finds what one is not looking for. When I woke up just after dawn on Sept. 28, 1928, I certainly didn’t plan to revolutionize all medicine by discovering the world’s first antibiotic, or bacteria killer. But I guess that was exactly what I did” (he was obviously a humble chap).

3) Cosmic background radiation.

IMGP0003 300x199 The best laid plans omice and researchers: my top 5 chance scientific discoveries. Any scientist can tell you how annoying inconsistent or noisy data can be, but not many could boast that noise actually won them a Nobel Prize.

In 1965, Arno A. Penzias and Robert W. Wilson were working for Bell Laboratories using a sensitive horn antenna to detect low levels of microwave radiation. As they scanned the sky with this device their findings were constantly overshadowed by a low level of background “noise”. Both scientists assumed that this persistent “noise” was an unwanted artifact and tried a huge range of techniques to eliminate it but their attempts were to no avail. However, after much head-scratching they finally discovered that another group of scientists from Princeton had already predicted that such “noise” should be detectable as a remnant from the Big Bang and were about to start looking for this themselves.

So it turned out that the annoying artifact that Penzias and Wilson spent so much time trying to eliminate was actually background radiation left over from the Big BangIf only experimental noise was always this interesting!

2) Drunk scientists discover wine improves super conductance

4360695477 b5f3f1a632 225x300 The best laid plans omice and researchers: my top 5 chance scientific discoveries. Contrary to the popular mathematician’s saying ‘don’t drink and derive’, it seems that, in some cases, a little bit of alcohol (or perhaps a lot) can actually facilitate scientific discovery.

A few years ago, scientists at Japan’s National Institute for Materials Science got a little bit tipsy at an office party and, instead of stealing office supplies, they decided to head back to the lab and do a few unauthorised experiments.

Their lab was working to develop a new type of superconductor by soaking a compound in hot water and ethanol for several hours. But, after a few drinks, one bright spark decided that it would be much more fun to see what happened when they instead soaked this compound in whatever left-over booze they could find from the party.

Amazingly the next morning, alongside the customary hangover, the researchers also discovered that commercially available alcohol seemed significantly better at improving super conductance than anything they would commonly use in the lab. Indeed, using lab- grade ethanol improved the material’s superconductivity by about 15%, while red wine improved it by almost 65%. These results were certainly not expected but were, without doubt, a big step forward for these scientists – I think it may be time for another party!

1) Common worming tablet inhibits growth of cancer cells.

3667927147 e452ddc04e 300x258 The best laid plans omice and researchers: my top 5 chance scientific discoveries. Scientists from Johns Hopkins University’s East Baltimore medical campus were left scratching their heads a few years ago when techniques used to grow tumors in mice failed to work on one particular group of research animals. After a number of failed attempts, the researchers decided that there was something kooky about these mice and set about finding what it was.

It turned out that these specific mice had been treated with a cheap, mass-produced, medication used to prevent pinworm infections and that this had been preventing tumor growth in these animals. Spurred on by this unexpected breakthrough, researchers soon found that a related drug – mebendazole – was particularly effective at treating an aggressive type of brain tumor (glioblastoma multiforme).

Years down the line and new drugs, stemming from this unexpected discovery, are now being trialed on terminally ill cancer patients with the hope that this will lead to more widespread use.

So there you have it. If you want to be a top-notch scientist remember that keeping your workspace sterile is totally overrated, regular office parties are a must and don’t forget to love your noise – you never know where it may lead you.

Post by: Sarah Fox
*Often go awry.

Posted in Sarah Fox | 2 Comments

Heretic to hero: Sir Harold Ridley and his sight-saving invention

It’s a strange phenomenon that some of the most revolutionarily successful people are initially rejected, scorned or unappreciated. Galileo, van Gogh, Darwin, Lovelace, Mendel and Austen were all vastly unpopular in their time, yet now we all take their scientific and creative contributions for granted. Sir Harold Ridley, the inventor of the intraocular lens, is another example of these late-sung heroes. His work saves the eyesight of millions of people across the world every year, but at first his idea of placing a plastic lens onto the surface of the eye was thought by peers to be impossible, laughable and even dangerous.

 Heretic to hero: Sir Harold Ridley and his sight saving invention

Cataract in a human eye. The pupil looks milky or cloudy. Image from Rajesh Ahuja, MD, Wikicommons.

The eyeball acts like a camera: light from the outside travels through the pupil and the lens to focus on the back of the eye, where the light is translated into images by light-sensitive cells that are located there. Due to age, trauma, toxic chemicals or certain diseases such as rubella or diabetes, the proteins that make up the lens denature and become opaque which prevents light from entering the eye and causes cataracts. People with cataracts suffer from very poor vision or blindness (see the image comparison); over half the world’s blindness (around 20 million people) is caused by age-related cataracts alone.

 Heretic to hero: Sir Harold Ridley and his sight saving invention

Normal vision. Image from National Eye Institute, NIH, Wikicommons.

 Heretic to hero: Sir Harold Ridley and his sight saving invention

Sight with cataracts: the image is blurry or out of focus, . Image from National Eye Institute, NIH, Wikicommons.

 

 

 

 

 

 

 

Over the course of history, several gory approaches to treating cataracts have been trialled. Somewhere between 2000-600BC, a procedure called ‘couching’ was used. This procedure involved using a sharp instrument, or just blunt pressure, to detach the cataract-riddled lens from where it normally resides into the back of the eye. Not surprisingly, this procedure was usually massively unsuccessful: patients usually suffered pain (as this was before a lot of modern anaesthetics were available), inflammation, infection and even blindness as a result. Even if the procedure and aftercare went smoothly, the patient was still left with inadequate eyesight. Unfortunately, couching is still performed in some developing countries where access to healthcare is often restricted.

As general surgical practice improved over the centuries, better tools and instruments were developed that allowed the opaque lens to be either removed, or broken up into small, more easily absorbable pieces. More often than not, patients were still left with poor eyesight and had to wear cumbersome, thick glasses to compensate for the missing lens.

 Heretic to hero: Sir Harold Ridley and his sight saving invention

Gordon Cleaver flew a Hurricane, the windshield of which was made from Perspex. Image from Tony Hisget, Wikicommons

Dr Harold Ridley, a recently trained medical doctor who specialised in ophthalmology, worked in the south of England during the Second World War. In August 1940, Flight Lieutenant Gordon ‘Mouse’ Cleaver forgot to put on his flight goggles before going out in his plane for what was to be Adlertag (Eagle Day) – the first day of Luftwaffe’s mission to eliminate the Royal Air Force from the sky. On returning to base, a bullet went through the side of Cleaver’s cockpit and shattered the Perspex window, a small fragment of which entered his eye. Cleaver had many operations on his face to treat the damage, but Dr Harold Ridley’s operation was to change medical history.

When Ridley removed the Perspex from Cleaver’s eye, he observed that there was no inflammation: the body hadn’t recognised the material as ‘foreign’ and so hadn’t initiated an immune response against it (as it usually does against materials like wood or metal). Ridley started thinking: if you could take the Perspex out of eye and there was no inflammation, then there would surely be no biological reason why you couldn’t put it back in.

 Heretic to hero: Sir Harold Ridley and his sight saving invention

A modern intracoular lens. The two arms help to fix the lens in place within the eye. Image from Wikicommons.

With this in mind, Ridley developed the first intraocular lens (IOL) – a small disc made from Perspex – and in 1949 placed it into the eye of his patient after first removing her cataract. With further modifications to improve the IOL’s power (that is, the ability of the lens to bend light, as glasses do), some of his first patients even attained 20/20 vision. Initially, Ridley sought to keep his patients’ implants a secret from the academic community until he could confirm from follow-up checks that there were no adverse effects, but a patient accidentally let slip the secret. So, in 1951 Ridley published his results and took two of his patients to be inspected by the Oxford Ophthalmological Congress. His work was rejected by other eye experts and deemed heretic. As a result, Ridley became a professional pariah and sank into depression.

Robert Young in Dangerous Number trailer Heretic to hero: Sir Harold Ridley and his sight saving invention

Actor Robert Young had an IOL implanted that allowed him to carry on working. Image from Wikicommons

But not everyone was so sceptical about the IOL. Foreign eye doctors saw the promise of the invention and in 1974  - 25 years after the first IOL implant – a Club was started with the aim of discussing the use of IOLs in cataract surgery. Robert Young, a famous American actor, underwent the procedure and sang its praises to the press. Only years after he retired in 1971 was Harold Ridley officially recognised by the ophthalmic societies and institutions. In 2000 he was knighted by Queen Elizabeth, but he passed away in 2001.

The long-unappreciated work of Harold Ridley is now recognised as not just an invaluable contribution to ophthalmic medicine, but also one of the first ever feats of bioengineering. Applying a scientific strategy such as using materials that are foreign to the body to fix a medical problem was previously unheard of, yet today we benefit from IOLs, dental implants and pacemakers to name just a few. Increasingly, bioengineering takes advantage of 3D printing and other advancing technologies and materials in the production of tissue grafts and implants that, like IOLs, will make such a huge difference to peoples’ lives.

 Heretic to hero: Sir Harold Ridley and his sight saving invention

A plaque commemorating Sir Harold Ridley’s achievement at St. Thomas’ Hospital, London. Image from Wikicommons.

Post by Natasha Bray

 

Posted in Uncategorized | Leave a comment

The evolutionary quirks of Australian animals

800px Reliefmap of Australia 150x150 The evolutionary quirks of Australian animalsAustralia is home to many interesting phenomena, amongst them its weird and wonderful wildlife. 86% of plants, 84% of mammals and 45% of birds found in Australia are not seen anywhere else in the world.

Australia became separated from the rest of the world when it broke away from Antarctica between 85 and 30 million years ago. The isolation of Australia, combined with its harsh, arid climate has allowed for the evolution of unique species, each filling a particular ecological niche.

Australia’s unique flora and fauna make it one of most fascinating places in the world to biology. The following is a highly scientific* ranking of some of the extraordinary creatures found in Australia, and why they are fascinating to science**.

#5 : The Kangaroo

kangaroo 300x224 The evolutionary quirks of Australian animals

Credit: Louise Walker

Kangaroos are marsupials, meaning that the females have a pouch in which they will rear the baby kangaroo (joey). Marsupials are also found in North and South America, but are most abundant in Australia.

Famous for using their very strong hind legs to bounce across the Australian plains, the kangaroo and its smaller relative the wallaby use this bouncing to travel great distances, allowing them to survive in the harsh desert conditions of their home country.

There are many different species of kangaroo. The largest, the Red Kangaroo, can grow up to 6 ft 7 in tall.

There’s a persistent rumour that kangaroos are so named because the first Western explorers asked the native Aborigines what those bouncing things were, and the Aborigine replied with their word for “I don’t know”, this being “Can-ga-roo”. However, this is not true, the word “kangaroo” actually derives from “gangurru”, the native word for a Grey Kangaroo.

#4 : The Koala

koala 300x224 The evolutionary quirks of Australian animals

Credit: Louise Walker

Another famous Aussie native, the koala is found on the east coast. Despite appearances and the fact that it is sometimes called a “koala bear”, it is not a bear at all. It is a marsupial and, like the kangaroo, rears its young (also called a joey) in a pouch.

Koalas famously subsist on nothing but eucalyptus leaves which makes them very slow and lazy. Some people believe that the eucalyptus has a narcotic-like effect on the koalas, a bit like being stoned. But the koalas’ sedentary lifestyle is actually due to a lack of nutrition in its diet leaves; meaning that digestion takes up a lot of energy leaving very little left over for things like moving. With regard to its picky eating habits, the koala may seem a little like its non-cousin the panda, in that they both spend all day eating something which isn’t actually very nutritious. The major difference is that koalas are voracious breeders. When the male is ready to mate, he makes a noise which has been likened to “a pig on a motorcycle”.

As you can see from the picture, koalas have two opposable thumbs. This allows them to climb trees and grab small branches with ease. A recent paper has also detailed that koalas adopt their famous “tree hugging” pose to help them lose body heat.

#3 : The Little Penguin

penguin 300x200 The evolutionary quirks of Australian animals

Credit: Fir0002/Flagstaffotos, commons.wikimedia,org

The smallest breed of penguin in the world, the Little Penguin stands at 30-35 cm in height. Found only in Australia and New Zealand, these penguins famously participate in the “penguin parade” on Phillip Island, near Melbourne. The penguins spend up to a month at sea feeding, but some will return to their nests at dusk, often to feed their hungry chicks.

When the time comes to return from the sea, the little penguins have evolved a great survival technique – they form groups of 10-20 in the sea, then choose one unfortunate penguin who has to make sure the coast is clear. This scout penguin runs up and down the beach a few times to make sure there are no predators so that the other birds can return safely to their nests.

For more information on the little penguin colony on Phillip Island, Victoria, see this link.

#2 : The Inland Taipan

snake 300x213 The evolutionary quirks of Australian animals

Credit: Bjoertvedt, commons.wikimedia.org

This snake gets the honour of being ranked number 2 because it is the most venomous snake in a country full of venomous snakes – which I think is quite a feat.

The title of “most venomous snake” was awarded to the Inland Taipan as its venom has the lowest LD50 score when tested in mice. This means that a very small amount of toxin is needed to cause death in 50% of subjects when compared to venom from other snakes. The Inland Taipan is also highly venomous when used on human heart cells in culture. One drop of venom is enough to kill 100 men.

Despite its highly venomous nature, the Inland Taipan is actually quite placid and rarely attacks humans. The world’s second most venomous snake, the eastern (or common) brown snake is generally more aggressive and has more fatalities to its name, according to this rather baffling Wikipedia list.

Although it is the most venomous snake in the world, the Inland Taipan is not the most venomous animal in the world. This honour is usually bestowed on the Box Jellyfish. Guess which country this comes from ….

Perhaps the need to be tough enough to survive Australia’s harsh environment may explain why the country contains an abnormally large amount of deadly creatures.

#1 : The Platypus

Platypus 300x214 The evolutionary quirks of Australian animals

Credit: John Lewin, commons.wikimedia.org

When the platypus was first discovered by early Western explorers, the scientists back home thought this duck-billed, beaver-like, egg laying creature was a hoax. The platypus and the hedgehog-like echidna (also Australian) are the only living examples of monotremes, or egg laying mammal. They are classed as mammals because they lactate and are warm-blooded (although actually their blood is cooler than most mammals).

Sequencing of the platypus genome in 2008 revealed that it shares genetic characteristics with birds and reptiles along with mammals. Because of this finding, monotremes are believed to have formed a separate branch on the evolutionary tree, very early into the evolution of mammals. This makes the monotremes especially fascinating to science because they give us clues about our evolution that no other animals can.

The reason that the platypus gets top ranking (as opposed to fellow monotreme the echidna) is the extra evolutionary level the platypus brings – the males have a venomous spur on their ankles which can cause severe pain and swelling in humans. This spur is believed to be used during fights between males for the attention of a female.

So there’s your number one weird Australian animal – frankly, what’s not to love about a furry mammalian bird-reptile which, when angered, will give you a nasty kick with its poisonous ankle?

*by “scientific” I mean “in my opinion”.

** this does not include the many varieties of spiders found in Australia for no other reason than I don’t want scary spider pictures on my blog.

Post by: Louise Walker

Posted in Louise Walker | Leave a comment

Can a brain scan reveal your true age?

TWO 192x300 Can a brain scan reveal your true age?For as long as carnivals and funfairs have been around, there have been people who try to guess your age; a trick that often goes hand-in-hand with horror at the response. With our ageing population, which is most likely due to advances in medicines, treatments and our understanding of diseases, age is quite topical.

A recent study has shown that observing  the anatomy of your brain may be able to uncover your true age. A set of biological markers has been shown to accurately predict the age of a young person’s brain. So, if you have ever told a white lie about your age at the cinema to get a child’s ticket, or if you ever tried to trick shop owners into thinking you were 18 so that you could be served alcohol or cigarettes then this could soon be a thing of the past!

Previous studies have tried to observe aspects of brain structure and function with the aim of identifying whether there are common patterns and timings during the development of our brains. Although many studies have been unsuccessful in trying to show this, a study carried out by Timothy Brown at the University of California combined a range of parameters regarding the structure of the brain in order to assess its age. Using 885 subjects aged between 3 and 20 years, individuals were selected from a diverse range of races, educational backgrounds and economic statuses.

Children can develop – in terms of mental capability and maturity - unpredictably, but what is not known is the extent to which these differences are based on physical features of their brain, and or are due to psychology or environment.

Magnetic resonance imaging (MRI) was performed on each of the subjects to look at the internal structure of brains, of which 231 features were studied, including certain structures, the connectivity between different regions, and thickness or volume of different areas of the brain.

oNE 285x300 Can a brain scan reveal your true age?Large variations in many of the measurements were observed that corresponded to the ages of the subjects. By combining the data from each of the measurements using a complex mathematical equation, an accurate ‘snap-shot’ of how the brain appears at each age during development was formed.  Although there were slight differences during development between brains of a similar age, the equation was able to correctly predict the age of a child to within a year, with an accuracy of 92%.

These findings indicate the presence of a developmental clock within our brain that produces a precisely timed development of brain structures throughout childhood.

Although these findings are incredibly interesting, aside from giving us insight into how our brains work you may be wondering what the relevance of these findings are. Whether we would be able to use the same technique to reliably determine the age of an adult by looking at the structure of their brain is another question. To be able to identify the true age of an individual has many advantages, but one of the most important clinical applications of this would be in observing whether a child’s brain is developing at a rate that is comparable to others of a similar age. It would also be useful in observing brain structures in individuals with autism, and other developmentally related disorders.

There are also non-clinical applications for this technique, such as cases where border staff need to be able to accurately determine the age of an individual without documents to be able to make a decision on whether to grant asylum. In the Olympic Games in Beijing in 2008, controversy arose when officials were unable to decide whether some of the competing athletes had entered the games illegally by lying about their age in order to compete.

To further this work, the study should address whether the anatomy of the brain is able to reliably predict age in subjects that have reached adulthood. If biomarkers are able to accurately predict our age even after development, then this could lead to rapid advances in the development of medicines for age and development-related illnesses.

Study: Neuroanatomical assessment of biological maturity – Timothy Brown et al. – Current Biology, September 2012.

Post by  Sam Lawrence

Posted in Uncategorized | Leave a comment