Anaesthetics & Alzheimer’s

Researchers at the University of Pennsylvania’s School of Medicine have discovered that common inhaled anaesthetics increase the number of amyloid plaques in the brains of animals, which might accelerate the onset of neurodegenerative diseases like Alzheimer’s.

Roderic Eckenhoff, MD, Vice Chair of Research in the University of Pennsylvania’s Department of Anesthesia and Critical Care, and his co-authors, report their findings in the 7 March online edition of Neurobiology of Aging.

Every year over 100 million people undergo surgery worldwide, most under general anaesthesia with an inhaled drug. These drugs clearly affect cognitive ability at least in the short term, but the growing concern is that inhaled anaesthetics may affect a person well beyond the perioperative period, even permanently.

Several factors appear to play a role in this subtle loss of cognitive ability, most notably age. A specific effect of these drugs on dementias like Alzheimer’s disease, though suspected for many years, has only been recently supported by data.

Genetic basis of autism

The genomes of the largest collection of families with multiple cases of autism ever assembled have been scanned in a new study. The results provide new insights into the genetic basis of autism, according to a report published online in Nature Genetics. Autism spectrum disorders (ASD) influence social interaction and communication and affect 6 out of every 1,000 children.

The Autism Genome Project Consortium – comprising 50 centres in North America and Europe – collected DNA samples from nearly 1,500 families, each of which has more than two members with ASD. The team carried out a two-fold analysis.

First they assessed the frequency of alterations in copy number of different segments of the genome, finding an unexpectedly high percentage of the families – 7 to 12%, depending on how the analysis was done – in which all affected individuals share possibly detrimental chromosomal abnormalities.

Two female siblings had deletions of the gene encoding the protein neurexin 1, which interacts with neuroligins — a family of proteins that have been implicated in some cases of autism. Finally, the authors carried out a ‘linkage’ analysis of these families, searching for regions of the genome that might be shared by the individuals with ASD.

One particular region on chromosome 11 was identified, which has not previously been reported to harbour genes that affect risk of developing autism.

Empathy skills

A paradigm shift in medical education is needed, one with more emphasis on training future physicians to enhance their empathy skills and to learn to view patients as persons, not just cases, a medical education specialist at Jefferson Medical College, Philadelphia, Pennsylvania, says.

“If we want to train physicians with more empathy, then education must shift from emphasising only the biomedical to also providing a biopsychosocial framework, as well and a more complete picture of patients as persons,” says Mohammadreza Hojat, PhD, research professor of psychiatry and human behaviour at Jefferson Medical College.

According to Dr Hojat, who has written a book, Empathy in Patient Care: Antecedents, Development, Measurement, and Outcomes, (Springer-Verlag 2007), much emphasis is placed on the biomedical paradigm of health and illness, which is akin to treating the organ affected by disease rather than curing the patient’s illness.

“The thinking is, once you treat the organ, the patient is fine,” he says. “This is a unidimensional approach to patient care. Health is not simply defined as absence of disease – it encompasses the physical, mental and social well being of a person.”

The book is aimed at physicians, medical students, residents, psychologists, clinical social workers and any other health professionals involved in patient care. It serves as a platform, he says, to discuss factors that contribute to empathy development, such as genetic, social and educational factors, and approaches to enhance empathy. Dr Hojat is convinced that a caregiver’s empathic abilities can influence how a patient fares. 
 
“It’s important to consider the potential role of empathic ability in clinical outcome,” he says. “When the patient feels the physician can understand him or her, that in itself seems to have a therapeutic effect.” In 2001, Dr Hojat and his colleagues developed the Jefferson Scale of Physician Empathy. The scale, which has already been translated into 15 languages and is used by researchers worldwide, is the only psychometrically sound instrument available for specifically measuring empathy among physicians and medical students.

Ophthalmoscope

A new digital ophthalmoscope, devised by a research team led by the University of Warwick in the UK, can provide both doctors and optometrists with a handheld eye disease diagnosis device equal to the power of bulky hospital-based eye diagnosis cameras. It will also give optometrists the ability to email detailed eye maps of patients to specialist eye doctors. 
 
Ophthalmoscopes, which act as an illuminated microscope for the eye, have changed little in design in the last century. As a result the effective operation of the device is constrained by the skill, expertise and eyesight of the eye specialist.
 
The new digital ophthalmoscope uses a combination of specialist lens digital imaging and lighting technology which for the first time allows a high quality digital image to be captured and recorded by an ophthalmoscope.

Type-2 diabetes genes

The most important genes associated with a risk of developing type-2 diabetes have been identified, scientists report in a new study. 
 
The research, published online in Nature in February, is the first time the genetic makeup of any disease has been mapped in such detail. It should enable scientists to develop a genetic test to show an individual their likelihood of developing diabetes mellitus type 2. The scientists believe their findings explain up to 70% of the genetic background of type-2 diabetes. 
 
In addition, one of the genetic mutations which they detected might further explain the causes behind type-2 diabetes, potentially leading to new treatments. The research revealed that people with type-2 diabetes have a mutation in a particular zinc transporter known as SLC30A8, which is involved in regulating insulin secretion. 
 
Type-2 diabetes is associated with a deficiency in insulin and the researchers believe it may be possible to treat it by fixing this transporter. Professor Philippe Froguel, one of the authors of the study from the Division of Medicine at Imperial College London, said: 
 
“The two major reasons why people develop type-2 diabetes are obesity and a family link. Our new findings mean that we can create a good genetic test to predict people’s risk of developing this type of diabetes. 
 
“If we can tell someone that their genetics mean they are pre-disposed towards type-2 diabetes, they will be much more motivated to change things such as their diet to reduce their chances of developing the disorder. We can also use what we know about the specific genetic mutations associated with type-2 diabetes to develop better treatments.”

Annotating the human genome

An important step in the effort to compile a complete catalogue of functional elements in the human genome was published in the March issue of Nature Genetics. 
 
A specific chemical signature of DNA sequences that promote the expression of nearby genes has been identified, and researchers should now be able to more accurately predict the location and function of these sequences. 
 
 Analysis of the complete sequence of the human genome has identified approximately 25,000 genes, but genes comprise only a small fraction of the genome. At least some of the remainder of the genome consists of sequences called promoters and enhancers that determine when, where, and to what extent each of these genes will be expressed. 
 
While promoters are typically found immediately adjacent to genes, enhancers can be located much further away, making it difficult to identify them. Bing Ren and colleagues examined 1% of the human genome and catalogued a number of different chemical modifications that are made to histones, which are proteins that bind to and package DNA, and are known to be involved in gene regulation. 
 
They found that the histones bound to known promoters are marked by chemical modifications that are distinct from those found on histones bound to enhancers. This information enabled the authors to accurately predict the location and function of promoters and enhancers that were independently identified, as well as identify a previously undiscovered enhancer.

Mastectomy

Women who have been diagnosed with breast cancer in one breast have a higher risk of contracting the disease in their opposite breast as well. 
 
A thorough examination of the opposite breast using mammography and ultrasound is therefore common practice. However, many tumours still remain undetected when using mammography. Magnetic resonance imaging (MRI) promises better results, as is shown in an international study involving the University of Bonn. 
 
In almost 1,000 women with a recent diagnosis of breast cancer in one breast, MRI helped identify 30 cancers in the seemingly normal opposite breast. In women with a normal (negative) MRI of the opposite breast, there was a 99.6% confidence that in fact no breast cancer was present - which means that if the MRI study is normal, preventive mastectomy of the opposite breast, which some women want, is definitely unnecessary. 
 
These findings have been published in the 29 March issue of the New England Journal of Medicine.

Award for Medison

Seoul, Korea-based Medison, a manufacturer of diagnostic ultrasound systems, has been awarded the prestigious Frost & Sullivan Competitive Strategy Leadership Award for 2007 for its strategic initiatives to establish itself as a leading enterprise in the European ultrasound market. 
 
“Medison has accomplished high growth in the world’s biggest and most advanced market, Europe, by aggressive strategies and customer-oriented management,” said Karthik Arun, head analyst, Frost & Sullivan. 
 
The company implemented an aggressive strategy to achieve a significant market share, particularly in the high-end 3D ultrasound segment across Europe. Medison commanded a market share of nearly 40% in the high-end 3D and 4D ultrasound segment in Europe last year.

Mobile health assistant

Fraunhofer researchers have developed a smart sensor network for monitoring cardiovascular patients. The researchers presented the ‘mobile health assistant’ at the CeBIT fair in Hanover, Germany in March. 
 
Six Fraunhofer Institutes have spent two years working on a system that can record the main cardiovascular functions 24 hours a day over a long period of time and enables communication with qualified medical staff. The key components of the mobile health assistant were developed in a joint Fraunhofer project entitled senSAVE (Sensor Assistance for Vital Events). 
 
Along with comfortable, easy-to-wear sensors that constantly measure all the necessary data and transmit them by radio to a PDA, the assistant has the necessary software to collect and analyse the flood of information and send it via Internet or mobile network to a telemedical support centre, where trained staff can assess how critical the situation is, advise patients over the phone, and call a doctor if necessary.
 
It was a challenging task to find suitable electrodes for channelling the ECG readings, as they would need to be in permanent contact with the patient’s skin for days at a time say the researchers. They developed a highly flexible dry electrode that can be woven into the elastic fibres of a sensor shirt. Potential wearers are fitted with their own tailor-made sensor shirt. The sheer pressure of the garment is sufficient to establish contact between the skin and the adhesive electrodes. A second layer of fabric covers the sensor wiring and the electronic circuit board.

The oxygen saturation of the blood and the pulse wave curve are determined by a pulse oximeter. Until now the pulse oximeter has been pushed over the index or middle finger with a commercially available finger clip. In future it will be integrated in a strap to be worn on the person’s wrist. From there, the readings will be radioed to a miniature computer, such as a smart phone or a PDA, which at the same time receives the ECG readings. 
 
The time difference between these two sets of readings yields the pulse wave transit time, from which it is possible in turn to deduce the blood pressure transit time – non-stop, 24 hours a day.

Prostate cancer test

Scientists at St George’s, University of London, are working on a blood test that uses DNA markers to identify prostate cancer cells that are shed into the bloodstream. 
 
The researchers have demonstrated that by measuring the levels of these markers, not only can an accurate diagnosis of cancer be made, but the stage the cancer has reached – whether it is still localised or already has spread and become metastatic – can be identified. 
 
In addition, certain markers, if switched on, will hopefully give information on how quickly the cancer will develop, and, therefore, when treatment must be introduced. The current, most widely used method of detecting prostate cancer is the serum Prostate Specific Antigen (PSA) test, which is only 50% accurate. 
 
Increased levels of PSA are elevated in non-malignant conditions, such as benign prostatic hyperplasia, prostatitis and even urinary tract infections. This new test, which is able to detect one prostate cancer cell among a sample of 100 million blood cells, is 95% accurate. The test is currently at the stage of validation, with further development regarding standardisation and formatting, and could be introduced on to the market next year.

Obesity and early puberty

Increasing rates of childhood obesity and overweight in the United States may be contributing to an earlier onset of puberty in girls, say researchers at the University of Michigan CS Mott Children’s Hospital, in the US. 
 
In a new study published in the March issue of the journal Pediatrics, the researchers reveal that a higher body mass index (BMI) score in girls as young as age 3, and large increases in BMI between 3 years of age and first grade are associated with earlier puberty, defined as the presence of breast development by age 9. 
 
This longitudinal study is unique in that it included girls younger than age 5 to examine the association between weight status and timing of puberty. “Our finding that increased body fatness is associated with the earlier onset of puberty provides additional evidence that growing rates of obesity among children in this country may be contributing to the trend of early maturation in girls,” says lead author and U-M paediatric endocrinologist Joyce Lee, MD, MPH.
 
Studies have suggested that girls in the United States are entering puberty at younger ages today than they were 30 years ago, says Lee. Since rates of childhood obesity also have significantly increased during the same time period, researchers have speculated that childhood obesity may be contributing to a trend of earlier puberty in girls. Studies have shown that earlier onset of puberty can lead to higher rates of behavioural problems and psychosocial stress.

Sound of nerves

A team of Danish scientists has shown that nerve impulses transmit by sound and that the common view that nerves transmit impulses through electricity is wrong.

Health worker shortage

A new international Task Force under the auspices of the Global Health Workforce Alliance was launched and met for the first time in Geneva in March to tackle the global shortage of health workers. 
 
With a shortfall of 4.3 million health workers worldwide, including more than 1 million in Africa alone, there is an urgent need to increase the number of doctors, nurses, health managers and other healthcare workers needed to face immediate health crises. 
 
Dr Margaret Chan, director-general of the World Health Organisation, welcomed the new Task Force saying: “The simple fact is that the world needs many more health workers. The world faces global as well as local threats to health. Infectious diseases have staged a dramatic comeback, and chronic diseases are on the rise. We cannot improve people’s health without staff to deliver health care. 
 
The task force will champion the need for significantly increased investment in the education and training of health workers in developing countries, and will build international commitment to practical action. It will focus on practical solutions and consider the need and scope for financial and technical support internationally.

Artificial spiral vein

The Times of London reports that doctors in England have invented a novel artificial vein that could offer hope to people with clogged arteries. 
 
The plastic artificial vein is “rifled” inside which encourages the blood to spiral when it flows through it, mimicking the normal corkscrew motion of blood through the body’s veins and arteries. Results from human trials of the new plastic vein – which is being developed for use in bypass operations – have shown a 100% success rate in the first six months. According to researchers involved with the development – the simple adjustment from a smooth to a rifled vein has produced remarkable results in human trials. 
 
Professor Peter Stonebridge, who set up Tayside Flow Technologies with John Dick and Graeme Houston, from Ninewells Hospital in Dundee, UK, to develop the product, was quoted in the report as saying: “One would have expected some of the bypass grafts [artificial veins] in the trials to have failed, but none have. They are all still going which is remarkable.” 
 
According to the report, seven out of ten “smooth” artificial arteries used in below-the-knee bypass operations fail in less than two years and about 40% of patients need a limb amputated. On that basis, approximately 20% of the new “spiral” veins implanted into the legs of 22 trial patients should have stopped working after six months. But so far all the grafts have stayed open and bloodflow speed has remained constant.

Amniotic stem cells

Scientists have discovered a new source of stems cells and have used them to create muscle, bone, fat, blood vessel, nerve and liver cells in the laboratory.
 
The first report showing the isolation of broad potential stem cells from the amniotic fluid that surrounds developing embryos was published recently in Nature Biotechnology. 
 
“Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well,” said Anthony Atala, MD, senior researcher and director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine, in the United States. The scientists believe the newly discovered stem cells, which they have named amniotic fluid-derived stem (AFS) cells, may represent an intermediate stage between embryonic stem cells and adult stem cells. 
 
They have markers consistent with both cell types. An advantage of the AFS cells for potential medical applications is their ready availability. The report describes how the cells were harvested from backup amniotic fluid specimens obtained for amniocentesis, a procedure that examines cells in this fluid for prenatal diagnosis of certain genetic disorders. Similar stem cells were isolated from “afterbirth,” the placenta and other membranes that are expelled after delivery. 
 
In addition to being easily obtainable, the AFS cells can be grown in large quantities because they typically double every 36 hours. They also do not require guidance from other cells (termed “feeders”) and they do not produce tumours, which can occur with certain other types of stem cells. 
 
The scientists noted that specialised cells generated from the AFS cells included all three classes of cells found in the developing embryo – termed ectoderm, mesoderm, and endoderm. In their high degree of flexibility and growth potential, the AFS cells resemble human embryonic stem cells, which are believed capable of generating every type of adult cell.


 

                                  
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