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Archive for August 4, 2013

Biting back: Taking the sting out of spider venom

The brown recluse spider has a nasty bite


Brown recluse spiders bite more than 7,000 people in Brazil every year causing serious skin lesions and even death. The anti-venom used as treatment comes at the expense of many animal lives. But could a breakthrough in synthetic spider venom lead to a more humane solution?

“The first time I was bitten, I nearly died,” says Adelaide Fabienski Maia, a school assistant from Curitiba.

“I put my shorts on in the morning and felt a bite but didn’t realise what it was. It wasn’t until the evening that my face started burning up. I looked at the bite area and it was red.”

Adelaide was soon rushed to hospital with the classic target-shaped lesion caused by the venom eating away at her skin.

It was only thanks to a dose of anti-venom that she’s still around to tell the tale.

But the anti-venom currently available comes with its own risks – mostly to the animals involved in the production process.

Venom is milked from thousands of brown spiders before being injected into horses. This triggers an immune response that creates life-saving anti-venom for humans – while drastically reducing the horses’ own lifespan.

Now scientists in Brazil have come up with a synthetic venom alternative that could save many of those lives.

Not so incy-wincy

The Loxosceles family of venomous brown and recluse spiders is found in North and South America, Africa, Australia and some parts of Europe.

At 6-20mm long, they are by no means the world’s biggest spiders. Even their bite is almost painless. But their venom can cause large sores and lesions through dermo-necrosis – literally “death of the skin”.

It is the only family of spiders in the world to cause the skin to die in this way. Scientists have linked it to a rare enzyme in the venom called sphingomyelinase D, which damages and kills skin tissue.

In a small percentage of cases where anti-venom is not administered quickly enough, people can die through organ failure.

But many more deaths – of spiders and horses – are caused through the anti-venom production itself.

“We milk the spiders once a month for three to four months,” says Dr Samuel Guizze, a biologist at the Butantan Institute, Sao Paulo’s pioneering centre for anti-venom production.

It involves one technician gingerly picking up a spider and giving it an electric shock while a second scientist rushes to draw the venom into a syringe.

As only a tiny squirt of venom is surrendered each time, it means that tens of thousands of individuals must be bred for milking.

“The amount of venom obtained per spider is very small,” says Dr Guizze. “We then inject the venom into horses and after 40 days the horses are bled and the antibodies [anti-venom] separated from the blood.”

Unsurprisingly, being injected with brown spider venom has an effect on the horses’ health over time. Their lifespan is reduced from around 20 years to just three or four.

Sadly, the spiders fare even worse – dying after just three or four venom extractions.

Alternatives to animals

Six hundred miles away at the Federal University of Minas Gerais, a breakthrough in venom technology promises to greatly reduce the anti-venom industry’s reliance on animals.

Dr Carlos Chavez-Olortegui is a senior biologist and spider venom specialist.

“We identified the parts of the venom responsible for creating antibodies, and we made a protein chain containing only these parts,” he told the BBC.

By making a man-made copy of the active venom ingredient, it means that real spiders could soon be completely superfluous to the process,

And, although horses will still be needed for the foreseeable future, the synthetic venom is non-toxic. This means that horses will still make the right anti-venom in their blood but without experiencing the poisoning effects of being injected with real venom.

Dr Chavez-Olortegui says this new technique will enable horses to be retired after a few years and go on to live a full life

Indeed in the future, he hopes animals can be removed from the process altogether.

A vaccine for the future?

But the study has also shown tantalising possibilities for creating a vaccine.

Trials have shown that animals injected with synthetic spider venom start to produce antibodies that protect them from the effects of real brown spider bites.

Chavez-Olortegui hopes that these results could eventually pave the way for a human vaccine.

“More tests are required to see if the level of immunisation is maintained long-term, but we believe we are on the right path to making a human vaccine soon,” says Chavez-Orortegui.

The potential vaccine is seen as a major breakthrough for science but could have only limited applications in the real world – as the cost of developing the vaccine is weighed against the chance of being bitten.

But in a country where 26,000 spider bites were reported in 2012 alone – 7,000 of which involved brown spiders – there could well prove to be quite a demand.

Adelaide Fabienski Maia, who has the dubious honour of living in the “brown spider capital” of Brazil, has since been bitten a second time.

Although they’re not naturally aggressive, brown spiders have a nasty habit of sleeping inside people’s clothes.

Unsurprisingly, Adelaide doesn’t fancy taking any more chances.

“If there were a vaccine, I’d take the whole family today.”


World’s Most Dangerous Spiders

Brazilian Wandering Spider
  • Brazilian wandering spider (Phoneutria fera– (pictured) According to the Guinness Book of Records it has the most active neurotoxic venom in the world. Just 0.006mg is enough to kill a mouse. If you’re lucky enough to survive then a bite can cause extreme pain for days, including a painful erection which can lead to impotence.
  • Brown recluse spider (Loxosceles spp.) –Found on all continents except Antarctica, this spider bites causes necrotic wounds (see main article).
  • Southern black widow spider (Latrodectus mactans) – The spider that kills most people each year in the US, it has venom 14-15 times more powerful than that of a rattlesnake.
  • Sydney funnel web spider (Atrax robustus– They have one of the most toxic venoms to humans of any spider, but there have thankfully been no known deaths since the introduction of anti-venom. They are aggressive when threatened. They also have a habit of falling into swimming pools where they can survive for many hours.
  • Red back spider (Latrodectus hasseltiiRed backs are one of the most recognisable species in Australia. It is the female that is most likely to bite. Children and the elderly are most at risk of succumbing to the venom and should seek immediate medical attention.

via BBC News – Biting back: Taking the sting out of spider venom.

Ultrasound ‘may stop kidney injury’ from surgery

Blood flow problems in surgery can cause kidney injury

Ultrasound treatments could be used to prevent a common kidney complication than can arise after major surgery, researchers suggest.

The work, published in the Journal of the American Society of Nephrology, was carried out on mice.

But the researchers said there could be a “rapid translation” to human studies because the treatment for acute kidney injury (AKI) was simple and routine.

Experts said the study suggested potential for new therapies.

AKI is the sudden loss of kidney function, which can easily develop in any sick person through infection such as pneumonia, diarrhoea or a heart attack.

AKI can develop after major surgery, such as some kinds of heart surgery, because the kidneys can be deprived of normal blood flow during the procedure.

Once it has developed, there are few treatment options.


The University of Virginia team exposed anesthetised mice to ultrasound using a routine clinical imaging system 24 hours before disrupting the blood supply to the kidneys.

They then found the mice still had healthy kidneys after blood flow was restored.

But in other mice, who were given a “sham” ultrasound, the same disruption led to significant kidney injury.

The researchers suggest the ultrasound treatment stimulated an anti-inflammatory response from the spleen that then protected the kidneys.

Dr Mark Okusa, who led the study, said: “Our studies using non-invasive ultrasound now provide us with an active treatment that appears to be simple, effective, and nontoxic for the prevention of acute kidney injury.

“To our knowledge this has never been described for the prevention of tissue or organ injury.

“Interestingly, we suspect that similar mechanisms that lead to kidney injury may also lead to lung, heart, and liver damage and that this form of therapy might be effective for prevention of injury in other organs as well.”

Prof Donal O’Donoghue, the former national clinical director for kidney care, who has called for action over the level of AKI, said the paper was interesting.

He added: “It suggests that there are protective strategies over and above good basic fluid and medicines management care that are the cornerstones of prevention.

“Studying the animal model further is the next step . But we also need to invest in AKI research in the UK.”

via BBC News – Ultrasound ‘may stop kidney injury’ from surgery.

C. diff test to predict patients most at risk

A test to predict which patients are most at risk from the Clostridium difficile (C. diff) infection has been developed.

The “accurate and simple” test could benefit patients, hospitals and health services around the world, scientists and doctors in Devon have said.

C. diff is a bacterial infection of the digestive system.

In 2011, there were about 2,000 C. diff-related deaths, according to the Office for National Statistics (ONS).

The research was carried out by the University of Exeter and the Royal Devon and Exeter (RD&E) NHS Foundation Trust, with the National Institute for Health Research in the South West.

In a paper published by BMC Infectious Diseases it said growing concern about the number of C. diff strains resistant to drug therapies meant the findings were exciting.

‘Better chances’

Dr Steve Michell, senior lecturer in molecular microbiology at the University of Exeter, said: “They identify a simple, accurate and robust method to identify those patients who are at risk of dying from a C. diff infection.”

The benefits to patients and potential savings to the NHS and other health services “would be immense”, he added.

The test’s “comparative simplicity” means it could be used by non-specialists within 48 hours of diagnosis, allowing earlier treatment.

Dr Ray Sheridan, consultant physician at the RD&E, said: “This really simple and quick tool, which any junior doctor could use in the middle of the night, quickly and easily flags up those who need a speedy and intensive treatment regime or more senior help.

“The quicker we get on with the right treatment for the right patient the better their chances of recovery are.”

via BBC News – C. diff test to predict patients most at risk.

Fallopian operation ‘may cut ovarian cancer risk’

Ovarian cancer is the fifth most common cancer in women in the UK.

A doctor has raised the idea of women at high risk of ovarian cancer having their Fallopian tubes removed as a precaution.

Cancer Research UK said there was no evidence how effective it would be.

The Hollywood actress Angelina Jolie had a double mastectomy to reduce her chances of getting breast cancer after finding out she had a faulty BRCA gene.

The same mutation can also cause ovarian cancer. Prof Sean Kehoe said removing fallopian tubes might help.

Some people with the mutation do have their ovaries and the connecting fallopian tubes removed to prevent ovarian cancer.

‘Avoiding earlier menopause’

Prof Kehoe, of the charity Wellbeing of Women and the University of Birmingham, argues that just removing the tubes could help many women.

He said: “The main advantage of this approach would be hopefully giving some protection but avoiding earlier menopause, as normally the ovaries would be removed.

“Recent studies suggest that the fallopian tubes may be the source of up to 50 per cent of so-called ovarian cancers, though research is ongoing.”

However, patients would still need to have a second operation later to remove the ovaries and Prof Kehoe admitted there was a “need to research this in much more detail”.

About 7,000 women develop ovarian cancer annually, making it the fifth most common cancer in women in the UK.

Taking contraceptive pill

Dr James Brenton, an ovarian cancer expert at Cancer Research UK, said: “Removing the fallopian tube from women with a BRCA fault could reduce their risk of developing ovarian cancer without the side-effects that removing the ovaries would have.

“But there have been no studies to show how effective this could be.

“Any woman who carries a BRCA fault should speak to her doctor to discuss the possibilities for them.

He said there were other things women could do to reduce their risk, such as taking the contraceptive pill for three years before the age of 30.

via BBC News – Fallopian operation ‘may cut ovarian cancer risk’.

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