Search This Blog

Sunday, 30 September 2012

What's new on health matters from Australia?

@HealthMed Recent news concerns infection alerts, raising awareness of the risks of overweight, and ethics of using social networking to undermine efforts to combat drinking and driving.

'Grabbable gut' as clue to being overweight.
How do you engage the public in long-term interest in benefits of keeping weight in check? The recent ‘LiveLighter’ Australian anti-obesity campaign campaign, supported by the The Heart Foundation, aims to improve recognition of overweight as a personal problem. The campaign includes dramatic pictures of internal excess fat, accompanied by images of a man who does not appear realise he has a weight problem - with the reminder that if you can 'grab your gut' ie have enough spare loose abdominal flesh to grasp by the handful, there is a problem.  In other cultures, 'spare tyre', or the advice 'if you jump up and down and it bounces you're overweight' ... have similar resonance. 
Some critics have complained that the campaign further lowers self-esteem in those who already feel under psychological threat - or simply claim that these messages won't work. This overlooks the obvious - increasing failure to perceive that a given build is excessive, with overweight becoming the norm, both in developed and less developed countries.
  Key challenges are more about how to raise awareness that weight is even a problem, why that matters, and what initial and long term sustainable measures will help to keep weight in check and avoid preventable long-term cardiovascular and non-cardiovascular serious health risks.
Raising public awareness is all the more pressing with recognition, for example from recent data from the US NHANESIII study presented at the European Society of Cardiology Congress in Munich, that relative overweight [based on increased waist-hip ratio] is more important than raised weight based on body mass index, for predicting increased risk of serious heart disease and other causes of premature death.

Random roadside alcohol checks
In parallel with public health messages about the risk of drinking with any alcohol in the blood, random alcohol tests are being used in Western Australia to discourage drivers from drinking.
Several different initiatives have been used in other countries. In France, by a new 2012 law breathalyzer kits are compulsory for all cars. In Sweden and the USA, alcohol ignition interlocks have been used for drink drinking offenders, and several other countries have piloted these schemes involving a breathalyzer coupled to the ignition – if any alcohol is detected, the car’s ignition is inactivated. Elsewhere, a timed arithmetic test is used as barrier to starting the car, based on the adverse effects of alcohol on brain function of even modest alcohol intake. Rather than accepting help not to drive when potentially a danger to pedestrians and other road user, some drunk drivers have been reported to use a friend or even pay a sober contact to beat the tests.
In Australia, booze bus spotters have been posting messages on social networking sites to warn drivers of its location. Worrying not least from the question how and when drivers are accessing these messages.

Rise in ’Ross River cases’
RossRiver virus, an RNA alpha virus and member of the togaviridae family of viruses, is spread by mosquito  bites and is endemic in Australia and several South Pacific islands. The illness was first reported in 1928. The main reservoir animals appear to be kangaroos and wallabies.
The features include rash and flu-like syndrome, the acute features usually settling within 12 months, with however some of those infected by the virus reporting subsequent long-term ME like debility.
Why now provide an update on the virus? Public health reports indicate a rapid ~5-fold increase in numbers of cases of Ross River disease in Western Australia over the past 3 years from, 332 in 2009-2010 up to 1570 in 2011-2012. This rapid increase has been attributed to increased numbers of the vector - mosquitos - due to a series of La NiƱa events [coupling of Pacific Ocean currents with weather patterns].  This has lead to an increase in rainfall in parts of Australia, the resulting humid conditions and increase in ground-water favouring greater breeding by mosquitos. 

Friday, 21 September 2012

Advances in Microcirculation 2013, Warwick

@HealthMed The British Microcirculation Society is holding its 2013 Spring meeting at the University of Warwick campus. This one day meeting is being organised by the BMS Young Investigators group

Title: Advances in Microcirculation 2013: Early Career Investigator Symposium

Date: Saturday 13th April
Venue: Medical Teaching Centre, Warwick Medical School, University of Warwick (building 42 on campus map)
Conference dinner and awards: Saturday evening, 13th April

Delegates: UK and international scientists from academic centres, biotechnology companies, pharmaceutical industry, and other interested professionals

Themes include:
  • Vascular inflammation
  • Angiogenesis
  • Regulation of permeability and blood flow

Peer-reviewed communications: oral and poster sessions

The conference includes a workshop on ‘Shaping your career in vascular research’.

Affordable accommodation is available on the Warwick campus - register early to avoid disappointment!

For further detailsemail the organisers.

Quarryman's headache: clues to drug discovery

Chemist Ascanio Sobrero

@HealthMed Glyceryl trinitrate - GTN (discovered by Italian chemist Ascanio Sobrero in 1846-1847) - is widely used to prevent or reduce angina, a key warning symptom of coronary heart disease. 
An early clue that GTN might have medicinal properties came from the observation that handling the chemical could result in severe headache. GTN is also known as nitroglycerine, an important component in early explosives.  Workers in early munitions factories developed vascular headaches. And quarrymen handling nitroglycerine-based explosives were also at risk of such severe headaches that resignation may have been preferrable to recurrent onset of these severe symptoms. 
This lead to trials of GTN in angina by Dr William Murrell, with publication of results in 1879 in the UK medical journal The Lancet, followed by increasing popularity in use of GTN as treatment. 
The major beneficial effects of GTN are due to relaxation of veins, so reducing the filling pressure in the heart. This in turn, through Starling's Law of the Heart, reduces the work of the main pumps of the heart, the ventricles. Nitric oxide is a vasodilator made in the body by the cells that line blood vessels, endothelial cells: work on this pathway resulted in the award of the Nobel Prize in Physiology or Medicine for 1998 to Robert F Furchgott, Louis J Ignarro and Ferid Murad for their discoveries concerning "the nitric oxide as a signalling molecule in the cardiovascular system". 
Anti-anginal effects of GTN result from the dilator response of veins to the additional nitric oxide generated from the GTN by vascular enzymes (including mitochondrial aldehyde dehydrogenase). And this effect on veins occurs at a lower concentration of the drug than needed to relax arteries. Headache as an unwanted side effect of the drug is due to an increase in blood flow in arteries in the head.  The chance of arterial headache developing can thus be minimised by spitting out any remaining GTN once angina has settled.

There had been an earlier report in The Lancet in 1867 by Dr T. Lauder Brunton from Edinburgh on use of an organic nitrite, amyl nitrite, to treat angina. There is now evidence that nitrite may act as a chemical signal, independent of its vasodilator and other effects through conversion to nitric oxide.

William Murrell's 1879 Lancet paper.

Tuesday, 18 September 2012

Updates from the European Association Clinical Pharmacology & Therapeutics

@HealthMed The EACPT is planning two major events in the Summer of 2013. 

Professors David Webb and Simon Maxwell are organizing an EACPT Summer School for young researchers to be held in their home city, Edinburgh, 6 - 8 July, 2013. The programme includes keynote talks by invited expert speakers, workshops, poster presentations, free communications and social events. 

And August 28 - 31, 2103, the 11th EACPT Congress takes place in Geneva, hosted by the Swiss Society for Clinical Pharmacology and ToxicologyOver 900 participants are expected to attend including health professionals, scientists, policy makers, biotechnology and pharmaceutical professionals and others with an interest in basic and clinical pharmacology, pharmacotherapy, drug discovery and development, regulatory affairs and related areas.

Sunday, 16 September 2012

Painkillers and hearing loss in women?

@HealthMed Researchers from Boston in the USA have reported that pain-killer use increases risk of hearing loss in women. Sounds worrying but worth looking at what the study involved and asking the obvious questions: are the findings credible and can they be generalised beyond the population in the report?

This was a prospective observational study of around 62,000 women in the US Nurses Study, the overwhelming majority of whom were of Caucasian origin. Information was collected on use of three types of painkiller - ibuprofen, acetaminophen (paracetamol in the UK), and aspirin. Nurses were following for 22 years on average.

What did they find? The rate of reported hearing loss from all causes was high at one in six over the entire population in the study. For those using painkillers, there was no link with hearing change with occasional use (once or less per week) or with aspirin whatever the reported frequency if use. For ibuprofen or acetaminophen (paracetamol), regular use for 2 days a week or more was linked to increased risk of hearing loss. The highest relative reported increase in risk was 1in 4 (24%) excess hearing loss linked to use of ibuprofen on at least 6 days a week. The authors state they are unaware of the specific mechanisms linking hearing loss to these medicines in their study.

What potential weaknesses are there in the study?
These include:
-   Noise exposure is an important cause of hearing loss; and of headaches, an obvious reason to be taking painkillers. There was no information available on noise exposure as a confounding cause of hearing loss. The authors acknowledge that is an important flaw in their study.
- Hearing loss was self-reported and severity of hearing loss not measured.
- No information was given on the dose of pain-killers used.
- Taking painkillers regularly from 2 days a week to every day suggests underlying medical problems which may themselves have had an impact on hearing. Co-morbidity accounting for the pain-killer use was not clear.
- Oddly there was no consistent increase in risk of reported hearing loss with increasing numbers of days a week of painkiller use: similar hearing loss reported with paracetamol 6 or more days a week, as for 2 days a week but more hearing loss when taken taken 4 or 5 days a week
- In this study aspirin was not associated with hearing loss but would be expected to be based on previous studies, including studies in men. This raises questions about the accuracy of data collection.

Are the findings generalisable to people outside the study group?
- These were mainly Caucasian origin women who were nurses working in the USA. It is unclear whether similar findings would have occurred in other occupational groups, ethnic groups or other countries. However there are biochemical mechanisms by which all these drugs, including aspirin, could affect the hearing system. Therefore it would be premature to suggest that aspirin would be a safe alternative painkiller with regard to hearing.

Further research is needed to explore whether these findings are due to painkillers or co-incidental, and if confirmed, to find out who is at particular risk. For the present, any risk appears relatively low and linked in this study only to women taking selected painkillers (ibuprofen or paracetamol) for several days each week over long periods. Any long-term use of pain-killers should be discussed with a medical advisor or pharmacist. People who have unexplained hearing loss and are currently on these medicines at least 2 days a week for long periods should seek advice from their medical advisor, pharmacist or hearing consultant.

Wednesday, 12 September 2012

Anti-depressants, benzodiazepines, newer sleeping medicines and risk of motor accidents?

@HealthMed: The following comments were in response to a new paper linking use of anti-depressants, benzodiazepines and newer sleeping medicines to increased risk of motor vehicle accidents.
These comments were part of the briefing on this paper from the Science Media Centre.

In a paper published in the British Journal of Clinical Pharmacology, Tsai and colleagues from Taiwan have reported a ~40-70% relative increase in risk of non-fatal driving accidents in Taiwan linked to prescription of a wide range of anti-depressants, benzodiazepines and newer Z-drug sleeping medicines. In their study, around 5200 people who had had motor accidents were compared with around 31,000 people with no history of accidents. The medicines appeared possibly linked to from 1 in 20, to 1 in 70 accidents, depending on the drug type. Obvious questions for pharmacologists, health professionals and the public are whether these findings are credible, and if so, generalisable to other parts of the world.
This Taiwan report was based on a case-control study – more open to bias than randomized trials. Although the researchers matched controls for age, gender and year of the accidents, they were unable to rule out differences in patterns of driving or in alcohol intake between the groups. Alcohol amplifies any impairment in concentration resulting from effects of drugs that act on the brain; and ethnic Taiwanese are commonly are intolerant of alcohol, due to genetic lack of the enzyme needed to break down alcohol.
It is also possible that the increased accident risk resulted from effects of underlying psychological or psychiatric disorders for which the drugs were prescribed e.g. through poorer concentration or indirectly through additional effects of sleep disturbance caused by the conditions under treatment, independent of the drugs. In addition the researchers noted that those who had accidents also had a higher burden of a range of non-psychiatric diseases, also recognized as increasing risk of accidents.
What do these results mean for populations in other countries? Several of the drugs implicated in Taiwan are not commonly used in other countries and there are several sources of bias indicating need for caution in interpreting the study. However other studies have stressed the need for caution when driving when using these types drugs. When these drugs are prescribed, patients should seek advice about risks of driving from their physician or pharmacist. In any event, patients on these drugs should avoid any alcohol when driving.

More information: Chia-Ming Chang and colleagues. Psychotropic Drugs and Risk of Motor Vehicle Accidents: a Population-based Case-Control Study; British Journal of Clinical Pharmacology; DOI: 10.1111/j.1365-2125.2012.04410.x

Prevalence of alcohol and other drugs in fatally injured drivers. Joanne E. Brady, Guohua Li.  Addiction. Published online August 20, 2012