New technique aids location of veins beneath the skin

Scientists have come up with a brilliant way of making the process of taking blood or positioning cannulas easier. The new technique relies on the ability of blood haemoglobin to absorb near infrared light, and the surrounding tissue to reflect it. This creates a digital image of the blood vessels under the skin, allowing the precise positioning of the needle to draw blood or administer drugs.

The readout comes from a device that is easy to use and relatively cheap to maintain, with some portable devices costing as little as £40.

This new technology has been marketed by a number of companies, under the trade names “AccuVein”,  “EasyVein”, “VeinViewer” and “Veinlite”. An Australian Red Cross study in 2014 showed that 53.4% of blood donors would be more likely to donate blood if devices such as “AcuVein” were used. And the vein visualisation technology was beneficial in 71.4% of cases where veins were not visible to the naked eye.

In the UK, “AccuVein” was licensed by NICE (National Institute for Health and Care Excellence) for the NHS in 2014. Such devices can be used when taking blood or setting up IV lines for drug administration. Vein visualisation technology is particularly useful in obese, elderly and dark skinned patients where locating veins may be more difficult.

Tests have shown that it reduces anxiety, pain and delays in treatment, a trio of positive results for both patient and health professionals.  

 

Gene therapy for sickle cell anaemia: a cut above the rest?

Gene therapy, once hailed as a potential panacea for genetic disorders, has had a bit of a rocky ride over the last 20 years but recent experiments suggest that the way ahead may be smoother. Scientists at Stanford University in California have found a way to correct a faulty haemoglobin gene in patients with sickle cell anaemia, using some of the most recent advances in DNA technology.

Sickle cell anaemia is an inherited disease that distorts the shape of red blood cells, resulting in clogged up blood vessels and acute pain. Haemoglobin is the protein in red blood cells that carries oxygen and the warped blood cells die more quickly than normally – shaped blood cells, leaving sufferers short of oxygen and fatigued.  In the UK, sickle cell anaemia affects more than 12,500 people and is the most common and fastest growing family of genetic disorders.

There is no cure and treatment relies on dealing with anaemia, increased susceptibility to infections and pain relief, with bone-marrow or stem cell transplants as a last resort for patients with severe disease. The disease has a recessive inheritance, such that it’s necessary to inherit two copies of a mutation in the haemoglobin Ggene, one from each parent. If each parent is a carrier, a child of these parents has a 50% chance of inheriting one copy of the mutated gene and becoming a carrier themselves, a 25% chance of being a carrier or a 25% chance of inheriting two copies of the faulty gene and having sickle cell anaemia.

In the latest study published in the journal Nature in November 2016, scientists corrected the faulty gene using a DNA cutting tool called CRISPR-Cas 9. This cuts out the faulty gene allowing its replacement with a healthy version from a donor. In mice experiments, the genetically-modified cells established themselves in the mice’s bone marrow cells producing healthy red blood cells. A senior author on the paper Prof. Porteus commented that now “we can take stem cells from a patient and correct the mutation and show that those cells turn into red blood cells that no longer make sickled haemoglobin.”

Although many early gene therapy trials have by and large been unsuccessful, expensive and sometimes even fatal, the use of new tools like CRISPR- Cas 9, is leading to a revival of interest. Now the CRISPR-Cas 9 modified gene therapy technique is set to be tested in human clinical trials for safety and then efficacy in sickle cell anaemia patients.

Milking Our Genes: Lactose Intolerance Explained

Lactose intolerance is still common throughout the world but the development of dairy farming in Northern Europe led to the evolution of individuals who can digest milk.

Most people cannot drink milk as adults, despite its importance as a cheap and nutritious food source. Scientists have shown that the gene which enables adults to digest milk appeared, and became predominant in Northern Europe, as dairy farming took off. The rapid spread of the lactase gene is an example of the power of natural selection to select for a gene with strong evolutionary advantages.

Symptoms of Lactose Intolerance

Symptoms usually appear 30 minutes to 2 hours after consumption of milk or milk-rich products. These can vary quite significantly in their intensity; commonly, symptoms include nausea, cramps, bloating, diarrhoea and flatulence.

Lactose intolerance is not the same as milk allergies; these are an immune response to milk proteins.

There is no known treatment for lactose intolerance. Unlike milk allergies, intolerant individuals cannot become tolerant by exposure to small, then increasing quantities of lactose. However, lactose intolerance is easily managed by avoiding lactose, particularly as lactose-free milk is available in most supermarkets.

Many of the symptoms are dose-related so avoiding dairy products completely is not usually necessary. Lactose intolerant people can still eat yoghurts and small amounts of hard cheeses to ensure regular consumption of calcium and other essential nutrients.

What Causes Lactose Intolerance?

Milk is a rich source of protein and the carbohydrate lactose, a major source of energy for babies and young children. Lactose cannot be absorbed intact in the gut: the enzyme lactase breaks it down into its component sugars, glucose and galactose, which are easily transported across the gut wall.

Most lactose intolerance in adults is caused by an absence of the lactase enzyme. This is a developmental adaptation. All mammals, including humans, have high levels of expression of lactase in early life when their sole source of food is milk. As weaning takes place, the gene for lactase is gradually switched off and lactase expression decreases. This begins at 2-3 years of age and is generally complete by 5-10 years old. This inability to produce lactase to digest milk is often termed lactase non-persistence.

Lactase non-persistence is seen in the majority of the world’s population, including most of Asia and Africa. For example, in non-pastoral communities, such as the Chinese, only 1% produces lactase into adulthood. Conversely in Northern Europe, particularly Scandinavia, and in some nomadic tribes of the Middle East and Africa, lactase persistence is much more common.

Genes Involved in Milk Digestion

The genetic ability to digest milk can be seen as an example of evolution in action. Domestication of dairy animals and the increasing availability of a nutritious and clean food source led to the selection of the genes for lactase persistence. This gave some early Europeans a huge survival advantage.

Analysis of DNA from skeletons of Neolithic Europeans (between 5800 BC and 5000BC) revealed that the lactase gene was absent. Despite the fact that these were some of the earliest farming communities in Europe, these Europeans would not have been tolerant to milk. Scientists believe that the lactase gene, allowing the digestion of milk, emerged after dairy farming really took hold, such that over 90% of northern Europeans now have the lactase gene.

As the human genome project revealed the complexity of human genetic inheritance and evolution, scientists are studying the genetic variants of the lactase gene. New variants have been discovered in pastoral communities in East Africa which may have evolved independently from and more recently than the European lactase gene.

Attention is now focused on whether persistence of the lactase gene is associated with rising obesity and associated diabetes in Western countries or whether in some cases it is protective. The jury is still out on the long term effects of lactase persistence but, with increasing use of large scale genomic studies, the answer is likely to emerge soon.

Genetic profile affects age of menopause

The average age of menopause in the UK is 51 years. This is partly determined by your lifestyle but recent scientific research is revealing the genes that account for a 50% link with your mother’s age of menopause.

The onset of menopause is associated with various health risks, such as cardiovascular disease, osteoporosis and breast cancer, increasingly important as the population ages. In 1900 the life expectancy for a women in the UK was 50, so many women would not have reached menopause before they died. In 2017, the life expectancy for a women is in the late 80s, at least 35 years after the onset of menopause.

Women are born with a finite number of eggs in their ovaries. During the monthly menstrual cycle, an egg is realised from the ovaries. If no fertilisation takes place, the lining of the uterus is shed in the monthly period. As the levels of fertility hormones change with increasing age, egg production and monthly periods gradually cease, often with accompanying symptoms such as hot flushes.

Menopause is said to have occurred when a woman has not had a period in the preceding 12 months. Natural menopause happens between the age of 40 and 60, with the average at 51 years. Premature menopause, occurring before the age of 40, is also of concern as women have children later in life. It is estimated that 1-5% of women have a premature menopause; in some cases, this is associated with surgery and/or the treatment of cancer. Studies of populations who use no birth control have also shown that fertility wanes significantly about 10 years before menopause occurs.

If you smoke around the time of the menopause, it will hasten its onset by 2 years. This only appears to apply if you smoke 14 or more cigarettes a day; the association does not hold up if you’re a light smoker or smoked in the past.

Although the evidence is clear cut with smoking, the jury is still out on other environmental influences. These include: race, education, BMI, number of children, age of first menstrual cycle, oral contraceptive use, breast feeding, alcohol consumption, altitude and even exposure to sunlight.  Reports are conflicting, partly because of the difficulties of studying menopause, which is defined retrospectively.

The age at which your mother or sister had their last period plays a large part in the timing of your menopause. Studies in twins and in mothers and daughters have revealed that approximately 50% of the timing of your last period is governed by your genetic inheritance. A Danish research team found that women whose mothers had an early menopause had significantly fewer eggs in their ovaries than those whose mothers had a later menopause.

Now scientists are beginning to dissect the genes involved. One gene which has emerged is carried on the X sex chromosome (women have two X chromosomes and men an X and a Y chromosome). Men who carry a particular form of this gene develop Fragile X syndrome with severe learning difficulties. Female relatives of Fragile X individuals do not tend to have developmental problems, but are at a 25% risk of menopause before the age of 40.

With the latest technologies techniques that scan the entire genome, containing all our genes, large numbers of people can be studied. Similar research has been done for genetic markers of obesity for example. “One thing that intrigues scientists is whether different genes act at different ages to explain the huge range in natural age of menopause,” says Dr Anna Murray (Lecturer in Human Genetics, Peninsula University Medical School, Exeter, UK). In the latest research, published in Nature Genetics, 56 genetic variants were identified from a cohort of 70,000 women. These variants were enriched in genes involved in repairing damaged DNA and in genes linked to delayed puberty, suggesting potential molecular links between the onset and end of the female reproductive lifespan. In addition, the study also found evidence that genetic variants leading to later menopause also increase breast cancer risk.

Understanding the genes that influence the age of menopause, and how defective DNA repair mechanisms affect the quality and release of eggs, may help the treatment of infertility and influence treatments for heart disease and breast cancer. This will be increasingly relevant as, with an ageing population, women can except to live approximately 40% of their lives after the menopause.

CURE – the influence of the mind over health and disease

Mind over matter is a mantra that echoes across the medical world. But, what does it really mean? Can our thoughts and feelings really influence our ability to heal ourselves and perhaps prevent us from getting ill in the first place? Jo Marchant has written an intriguing book on the subject and I’ve just bought tickets to hear her speak about Cure at the Royal Institution on Thursday January 19. It promises to be a fascinating evening.

A stroke of bad luck at the hairdressers

Head bent backwards over the sink, having my hair washed, with the massage chair on full strength, a stroke is generally furthest from my mind. For one unfortunate man, it became a reality. Dave Tyler, aged 45, went for a routine haircut in a Brighton hairdressers and two days later had a stroke. In hospital, doctors asked whether he’d had his hair cut recently.

I thought of this story again when I went to our local hairdressers, part of the same nationwide chain. After a claim from Dave Tyler’s lawyer that the salon had offered insufficient neck protection, the hairdressers settled before the case when to court, with a pay out of £90,000. I wondered about discussing this with the girl washing my hair.  But she was full of the Christmas spirit and it seemed churlish to lower the tone, so I kept my musings to myself.

Primed for the Christmas festivities with a new haircut, and thankfully no other ill effects, I’m still wondering about the science behind this seemingly freak occurrences. Looking through the medical literature, it has been reported before, but it’s a pretty rare occurrence, with only a few cases reported. For example, in 1987 there was a report in the medical journal The Lancet which described the case of a 42 year old woman who’d had a stroke after having her hair washed.

A stroke happens when the blood supply to an area of the brain is cut off, usually by a blood clot (an ischaemic stroke) and more rarely a bleed (a haemorrhagic stroke). When the brain is deprived of the blood-borne oxygen and nutrients, the brain cells are damaged and/or die leaving the sufferer with impaired thoughts, speech or movements.

It does seem likely that some individuals may have a weakness in an artery supplying the brain, possibly from previous trauma, which predisposed them to a stroke from having their neck extended over a basin or similar situations, such as neck manipulation at chiropractors. An artery may be damaged, leading to a blood clot that can travel to the brain. Two days after his haircut, Dave Tyler began suffering from headaches and he collapsed at work. Two years later he still has blurred vision and, although he can walk again with a stick, he can’t drive or sail his dinghy.

In January 2014, a Californian woman, who’d also suffered from the so-called  beauty parlour syndrome, conducted an informal survey and found that 80% of hairdressers were aware that a stroke was possible after having your hair washed. But, the UK Stroke Association have stressed how small the risk is and suggested that hairdressers minimise this risk by cushioning the neck further with towels and avoid excess pressure on the neck.

BrainCanDo – rewiring the teenage brain

Schools are constantly on the lookout for ways to help teenagers understand their behaviour and use that knowledge to boost their learning, manage stress and stay healthy. BrainCanDo is an ambitious research project studying the teenage brain, initiated by Julie Harrington (headmistress of Queen Anne’s, an independent girls school in Caversham, Berkshire) who has a keen interest in neuroscience.

The project set out to understand how normal everyday activities such as eating breakfast and riding a bike become automatic and second nature. What areas of the brain are involved and how can we improve memory to deal with stressful situations like exams? Since its launch three years ago, students at two state schools (The Grey Coat Hospital and Westminster City School) and two independent schools (Emmanuel School and Sutton Valence School) have been involved.

Working with scientists from three universities (Oxford, Reading and Goldsmiths, University of London) a variety of project have been initiated including: how music can make you smart, the power of positive thinking, why humming music helps girls do maths, managing stress and why getting the giggles is contagious.

By learning how the brain operates in different situations, these research projects are helping scientists and teenagers understand the plasticity of the teenage brain and how wiring the right corrections at this crucial stage in life is so important.

Saving marine life with an edible 6 pack beer holder

Drinking is in the headlines again but not for the usual health reasons. A small brewery in the United States has made an edible six pack for beer that is biodegradable and edible.

Americans drank 24 billion litres of beer in 2015 and 50% of that was sold in cans. Many of the plastic ring holders end up in the sea, with hugely detrimental effects to marine life. An estimated 1 million sea birds and 100 thousand marine animals, such as sea turtles, eat the rings or are caught up in them, often dying as a result.

Saltwater Brewery in Delray Beach, Florida, have come up with a solution. Their ring holders are made of barley and wheat remnants from the brewing purchase: edible and biodegradable, these are strong enough to replace the plastic alternative.

Environmentalists have expressed concern about the effects of this edible product on the food chain and suggest that limiting the litter in the first place would be preferable. But a ring that feeds animals rather than kills them is a first for the beer industry. As craft breweries expand their market share, the edible rings are attracting interest from other breweries, potentially reducing production costs.

At 10-15 cents per unit, it’s still a snip – a small price to pay for saving marine life.