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Protecting the brain from stroke

It only takes one small clot to cause a stroke. Blocking a blood vessel in the brain, a clot starves cells of oxygen and thus triggers their untimely death. Now a new drug under investigation appears to protect nerves from damage and increase the chance of a recovery.

“When blood flow to the brain is blocked there is an increase in highly reactive, charged molecules called free radicals,” says Jonathan Marshall from the Comparative Cognition Team in Cambridge University’s Department of Clinical Veterinary Medicine. “These are highly dangerous and can cause nerve cells to prematurely die, so we have been working on a compound that mops up the free radicals and therefore save cells from death.”

Working with drug firm AstraZeneca, Dr Marshall has tested the effects of the drug, NXY-059, in monkeys that have undergone a moderate stroke. The researchers monitored the animals’ ability to perform several tasks that required them to reach for food before and after the stroke. They later took samples from these animals to quantify the extent of brain damage.

“Our experiments show that NXY-059 has substantial protective effects,” says Dr Marshall, “not only at reducing the amount of brain damage we observed in samples, but more importantly, at reducing the functional disability that follows a stroke.”

Dr Marshall adds that the most impressive effect of NXY-059 was to reduce the impairment that monkeys sustained in their arms. “Stroke victims often lose motor function on the opposite side to where the brain damage occurs. The monkeys that received NXY-059 readily used their affected arm at near normal levels 10 weeks after the stroke and were more likely to uses their disabled limb. They did not neglect one side of space as is frequently the case in stroke patients.

NXY-059 did not just enhance the natural rate of recovery but also reduced the long-term disability in these monkeys. This is important; large strokes are associated with permanent disability and poor recovery in humans.”

Dr Marshall is continuing his work looking at treatments for stroke. Recently his research team conducted safety testing for NXY-059 in clinical trials; the compound did not cause any adverse side effects. It is now hoped that large scale clinical trials will begin soon to assess the drug’s efficacy in stroke patients.

“The drug may have valuable applications in a wide range of brain damage,” concludes Dr Marshall, “including head injury and birth complications, and reduce long term disability following stroke. It could really help patients regain their lives and provide substantial cost savings to Health and Social Services.”

Stereotypes that contradict health advice are rare

When it comes to promoting healthier lifestyles, getting past the stereotypes is often a major challenge. Every time you say “Don’t smoke” someone will point to ‘Uncle Norman’, a familiar male figure who ignores medical advice and lives to tell the tale. Suggesting regular exercise provokes a debate on ‘the Last Person’ (you’d expect), who dies at a young age from a heart attack despite taking medical advice and living an exemplary lifestyle.

Researchers from the Medical Research Council Social and Public Health Sciences Unit at the University of Glasgow have now shown that these two stereotypes do exist, but are few and far between.

In a survey of 6000 Scottish men who were first studied in the 1970s and followed up for more than 25 years, they identified a group of 193 overweight, heavy smokers normally considered at high risk from a heart attack. Only half of these survived to the age of 70; around a quarter still died of a heart attack before that age.

Among the ‘low risk’ group of 337 men who had never smoked and who were the correct weight, the mortality rate was very low. Only 12 people, or one in 25, died of heart disease before the age of 70.

The majority of these ‘Last Person’ deaths were associated with other less obvious risks for heart disease, such as poor lung function, diabetes, previous heart disease and poorer social circumstances. Similarly, three quarters of the surviving ‘Uncle Normans’ had protective factors such as being taller and having lower cholesterol levels.

“Our assessment shows that the ‘Last Person’ is indeed a rare occurrence but looms large in public consciousness because such deaths are dramatic, unexpected and premature,” notes Dr Kate Hunt, one of the study’s senior researchers. “In addition to the trauma to immediate families and friends, such deaths often make a large impact locally and nationally through media coverage.”

Dr Carol Emslie, another investigator, adds, “‘Uncle Norman’ is not as common as people think, but it is true that there is a very small group of men who appear relatively immune to coronary disease risks. It is important for health promotion to acknowledge the existence of ‘Uncle Norman’ while emphasising that general healthy living advice is relevant to the vast majority of us.”

‘The Last Person’ and ‘Uncle Norman’ are both real people, but they are both rare. What is more important is the huge difference in coronary mortality between men at high and low risk. Using ‘Uncle Norman’ or ‘the Last Person’ to defend a poor lifestyle is dangerous – they are both outsiders. You should not bet against the established risk factors for heart disease.

Fat tally at supermarket checkout

They say you are what you eat, but at least only you know how much you ate this Christmas. However, a team of scientists now say that the secret’s out. Just by looking at your supermarket till receipts, they can estimate your consumption of fat and energy intake.

“Over 90% of our food is bought from supermarkets,” says Joan Ransley, Director of the Public Health Nutrition Unit at Leeds University. “We thought that till receipts would tell us lots of information about the nutrition of households.”

The research team studied the four weeks’ worth of receipts from 284 shoppers who said they spent at least 60% of their food bill at Tesco and at other supermarkets. Each member of the household also kept a four-day food diary. All the food eaten at home was weighed and meals eaten elsewhere were recorded and used in the analysis.

The analysis showed that the on average around 36% of a household’s energy intake comes from fat – 3% above the recommended levels set by the Department of Health.

“This pilot study shows a strong relationship between the amount of energy and fat purchased from supermarkets and the amount consumed,” says Dr Ransley. “Assessment of individual food consumption is prone to under reporting and inaccuracies. Therefore, the use of till receipts could be a novel, inexpensive and effective way of evaluating household food consumption.”

Wider studies could assess the nutritional intake of individuals and specific groups in society and examine diet-disease relationships between different geographical regions and countries.

“Supermarkets could play a role in helping us reduce the amount of fat in our diets,” suggests Dr Ransley. “Advances in scanning technology could lead to the development of a ‘fat tally’ of the foods in our trolleys and this could be shown on a graph on the receipt, plotted against the UK recommended levels of energy from fat.” It might be just enough to encourage you to put the triple choc, sticky toffee doughnuts back on the shelf.

Proteins put up a radical defence against ageing

When cells use oxygen to release energy from food, they produce a by-product called superoxide. A highly reactive free radical, superoxide can set off a chain of reactions that damage the structure of the cell and its genes, and can lead to degenerative diseases, ageing, and eventually death. Scientists have now shown that certain proteins can move the harmful superoxide from where it is made to other areas of the cell where it is destroyed safely.

These uncoupling proteins could be important in the natural antioxidant system in cells that guards against damage caused by free radicals and other oxidants. Antioxidants protect cells by eliminating reactive oxygen molecules like superoxide. Other known antioxidants are vitamins E and C. Diets high in fruit and vegetables have strong health benefits partly due to the antioxidant properties of these vitamins.

Oxidative damage has been linked with many ailments such as cardiovascular disease, strokes, autoimmune diseases like arthritis and diabetes, cancer and Alzheimer’s disease. By understanding the role of uncoupling proteins in cells, new treatments for these conditions could be developed.

Commenting on his findings, Dr Martin Brand of the MRC Dunn Human Nutrition, says that the role of uncoupling proteins could be fundamental to protecting against degenerative disease and ageing. “We hope that by understanding their role, we can find potential new ways to prevent or treat free radical linked diseases. For example, we might be able to decrease cellular ageing by using chemicals that switch these proteins on. However, we need to do more research to find practical or medical applications of these exciting new findings.”

The right height for your hips

The right height for your hips

If you want life to begin around 40 then you have to invest during childhood. Many medical conditions that appear in adult life find their beginnings in infancy. A team of scientists from the Medical Research Council’s Environmental Epidemiology Unit has now discovered that people who had poor height gain in childhood are more likely to fracture a hip during adulthood.

Led by Professor Cyrus Cooper of Southampton University, the research analysed over 7,000 medical records of people born between 1924 and 1933 in Helsinki, Finland. The documents recorded their size at birth, growth and living conditions in childhood and their hospital admissions in adulthood.

Statistical analysis showed that the slowest growing children were more likely to suffer a hip fracture. “This is the first time that researchers have had hard evidence that low childhood growth rates are linked to hip fractures in adult life,” comments Professor Cooper. “It seems likely that environmental influences which modify childhood growth are responsible.

“Such influences could include a mother who smoked in pregnancy or who had a poor diet, exposure to infections during infancy and early childhood or low calcium intake and lack of physical activity in later childhood.”

A separate analysis revealed that people who had a mother taller that 1.6 metres were also at increased risk of hip fracture. The researchers finding suggests that fractures might arise from a conflict between the genetic drive for bone growth and the environmental influences which affect the mineralisation of bones during childhood.

Both studies show the importance of a healthy diet in childhood. Just as a wall is more likely to collapse if a builder skimps on cement powder in his mortar, newly formed bone is structurally weak when children do not receive sufficient nutrients to match growth.

As the body of evidence into the childhood causes of adult medical conditions grows, governments and health institutions should begin to see the economic benefits of investing in childhood nutrition as a means of medical prevention for later in life.

A talking point for intensive care

A stay in an intensive care unit may only be short, but it is a worrying time for all concerned. On top of the anxieties regarding recovery, many patients, with breathing tubes in their throats, are unable to speak. A research project has now developed a computerised system that allows patients to communicate better by choosing sentences from a pre-programmed selection.

“Many patients in intensive care attempt to mouth words, but if they have tubes in their mouth, lip reading is difficult. Weakness can affect the movement of their hands and arms and make writing or gesturing hard too,” explains Professor Ian Ricketts from Dundee University. “The inability to communicate can be upsetting for patients and while nursing staff are highly skilled at anticipating the communication needs of patients, they say it is time consuming and difficult.”

Professor Ricketts has led a team from the Department of Applied Computing that has designed a system which enables patients to speak to staff, relatives and friends through a computer. They can navigate through a database of over 250 phrases using a touch-screen, a mouse or options using a single switch. The computer then uses speech synthesis software to utter the sentence.

“The selection of phrases available are wide ranging,” says Professor Ricketts. “We asked nurses to suggest sentences for particular topics and used their responses, along with observations of patient communication in our local intensive care unit, to compile a core set of phrases.”

Along with these stock phrases the research team devised a way that would supply patients with personalised phrases too. “We have a questionnaire that is completed by a family member and the answers are incorporated into template phrases to personalise them,” explains Professor Ricketts. “A patient can then enquire about a family member by name, for instance.”

The computer interface is simple to use, so patients easily learn how to use it. Phrases are grouped within eight colour-coded topic areas, such as “Family, friends” or “Feelings”. Trials so far show that patients quickly learn to control the system and successfully communicate. Nursing staff overwhelmingly support the concept of computer-assisted communication.

“Preliminary trial results have so far been encouraging, though of course we are still refining our prototype system, especially the navigation of phrases,” Professor Ricketts notes. “At the moment some phrases are hard to find or don’t exist, and we are also looking at incorporating animation into the navigation as research suggests that animation makes interaction with computer systems easier. Our main concern, however, is to make the system much smaller so that it doesn’t obstruct nursing staff or restrict their view of, and access to, the patient. Ideally a small, robust, bedside system will make communication much more natural and take one worry off the minds of patients, staff and relatives alike.”

Statistics that count in the animal kingdom

Statistics that count in the animal kingdom

A team of British statisticians is pioneering new ways of analysing information about how animals survive in the wild. The new techniques will give biologists a better understanding of the viability of populations of particular species. It will also help them to devise conservation programmes.

At the University of Kent at Canterbury, Professor Byron Morgan is developing statistical tools to improve the interpretation of the data on animal survival. Researchers can gather vast amounts of data over many years. But it can be difficult to make sense of the information and to relate it to what is actually happening to the population.

Data on the survival rates of animal populations not only yield information about the species itself but can also be an important indicator of environmental change. One way of obtaining this sort of information is to capture some of the population, mark them by placing a ring on the leg, for example, and then release them. The researcher then records sightings of marked animals along with details of the bodies of dead animals they find.

Professor Morgan’s team has devised a way of combining data from the recovery of dead animals with that from observations of surviving animals. This is significant because until now researchers have usually analysed the two types of information have independently. By integrating the data, experts in animal populations can make much more realistic conclusions.

The Canterbury team has also written software to help to choose the best statistical model for the type of data at hand. Data gathered from the field can be highly complex. Many factors can affect survival rates. With the new software, the operator feeds in the initial data, the software then prompts the researchers to indicate the most important parameters.

Using the data and the information from the operator, the system can help to select the best model population. Furthermore, the Kent team has developed a way of verifying if a particular statistical model is suitable for the kind of data that it is being presented with. The system allows the user to ‘interrogate’ any model to see if it is capable of analysing the data meaningfully.

DNA gives hope for TB vaccine

by Mike Miller
DNA gives hope for TB vaccine

Scientists will soon launch the first clinical trial of a new, but controversial, vaccine for tuberculosis (TB). Analysis from laboratory testing, moreover, shows that the vaccine may go beyond traditional preventative vaccines. It also works as a therapeutic treatment for patients who already have the disease…

Pager jogs memory and helps rehab

by Mike Miller

Brain injury often causes memory problems. Patients may miss appointments, forget medication, neglect their work. Diaries can help, but have to be checked; digital organisers are complicated to use. Consequently, people with memory problems begin to depend on others – a spouse, family member or carer – to remind them and organise their lives. Independence is lost.

NeuroPage is a radio-paging technology that reminds users about things they need to do. The concept was originally developed in California by a neuropsychologist and the father of a young man who suffered a brain injury. The service, launched in the UK at the end of 2000, is run by the Oliver Zangwill Centre for Neuropsychological Rehabilitation at the Princess of Wales Hospital in Ely, Cambridgeshire.

The individual wears an ordinary pager and reminders are stored on a central computer. Reminders might be for ‘one-off’ events such as hospital appointments or buying a birthday card. They can also be regular events or tasks, such as checking a to-do list, taking medication or getting ready to go to work or college. At the appropriate time, the computer automatically sends the message to the individual’s pager. A bleep or vibration notifies the wearer, who presses a button to read the message.

At any point users can contact the NeuroPage office (by telephone, letter, fax or email) and update their regular messages and add any ‘one-off’ reminders they may need.