Dendrocnide moroides aka “gympie gympie”

The Dendrocnide moroides has been said to be the plant with the most excruciating sting in the world- injuring and sometimes killing dogs, horses, and even humans. The species is relatively common in Queensland, and is native to the warm forests of northern Australia; typically growing 1.5-2 meters in height. The plant has large, thin heart-shaped leaves, which are covered in small silica-tipped hairs, which are extremely efficient at penetrating the skin of its victims. Contact with these hairs causes the release of the potent toxin moroidin, which causes the long list of agonising symptoms. One reason why the plant is extremely dangerous is that the hairs are very loosely fitted to the cuticle of the leaf, meaning that with light winds, the hairs can be blown off the plant and cause irritation if it comes into contact with an animal. On case of the sting resulted in suicide, after a man accidently used a leaf as a piece of toilet paper. The hairs of the plant can be embedded in the skin, and can remain there if no appropriate treatment has been given, which results in long-term pain and discomfort, which is one of the reasons why the plant is so feared- as the symptoms can sometimes last for weeks, if not months.

Moroidin is the active chemical in the toxin of the plant, and is a bicyclic octapeptide. Its skeletal formula is shown on the adjacent diagram, and it has a molecular formula of  C₄₇H₆₆N₁₄O_{10. It is made of 9 different amino acids.} 

The recommended treatment for skin exposed to the hairs is applying diluted hydrochloric acid and then pulling out the hairs with a hair removal strip. Tweezers or sticky tape can also be used, but care needs to be taken when removing the hairs, as if broken they will worsen the pain.

Analgesics and Anaesthetics

An analgesic is a drug acting to relieve pain, and this group of drugs include aspirin, paracetamol and ibuprofen[1]. These three drugs all fall under the most common type of analgesic- non-opioid analgesics. This group of simple painkillers work by blocking the COX-2 enzyme which is responsible for pain and inflammation[2]. The stronger groups of painkillers are compound and opioid analgesics, and these are widely used in hospitals for severe pain.

Aspirin is one of the most common analgesics used today[3]- the very first use of this drug dates back to ancient Asian records 2400 years ago, as a related compound from willow bark had been used to relieve pain and treat fevers[4]. The use of this compound then grew in the 18^th Century, with Edward Stone reading a paper to the Royal Society of London on the effect of willow bark on Malaria. In the 1840s, nearly 100 years later, organic chemists identified this active ingredient as salicin- which was found to be converted into salicylic acid in the body by Pr. Von Nencki in 1870. This was then given to patients to help with fevers, however a common and unpleasant side effect was soon discovered; severe irritation of the lining of the mouth, gullet and stomach.

To combat this chemists made sodium salicylate to cause less painful side effects, but it tasted awful and so patients were not keen on taking it. This also caused patients to vomit and so was not an ideal painkiller. In the 1890s Felix Hofmann of the Bayer (a German pharmaceutical company) synthesized a similar drug which was found to have good medicinal properties and be less irritable towards membranes in the body; aspirin had now been made.

Aspirin, or 2-Ethanoyloxybenenecarboxylic acid, was sent off for clinical trials and was finally patented by Bayer in 1898[5]. John Vare won the Nobel Prize for medicine in 1982 for discovering that aspirin inhibits the COX-2 enzyme in the prostaglandin pathway, and this drug is now one of the most manufactured in the world, with 10 million kilograms being made in the US each year.

An anaesthetic is a drug that causes anaesthesia, which is a reversible loss of sensation[6]. These contrast with analgesics, which relieve pain without eliminating sensation. These drugs are generally given to perform surgery or an invasive surgery, which would be very painful if the area could be felt by the patient. The main two types of anaesthetic are local and general anaesthetics.

Local anaesthetic is a form of medication that causes reversible absence of pain sensation in a localised area, although other senses can also be affected. Paralysis can also be achieved by this type of anaesthetic when used on specific nervous pathways[7] (this is known as an epidural, and is commonly used during a caesarean section during childbirth). The other two main types of local anaesthetic are topical and subcutaneous anaesthesia. Topical anesthesia is a local anesthetic which is applied directly to the skin- mostly in the form of a gel or a cream. Subcutaneous anesthesia as local anesthetic applied directly under the skin, mostly in the form of an injection, targeted at the nerves which stimulate pain in that specific area.

A common local anaesthetic is lidocaine[8], and we can use this example to see how many other local anaesthetics work. The main action of this drug is to inhibit the movement of sodium into nerve cells, but why does this effectively stop the feeling of pain? Figure 5 shows a representation of an electrical signal inside a nerve cell (axon), and how sodium ions move through sodium channels to stimulate the feeling of pain[9]. It then shows how lidocaine- represented as a red circle- blocks these channels and so does not allow the sodium to pass through the channel, and does not allow the electrical signal travel to the brain.

Figure 6 is a magnified version of figure 5 and shows the cellular membrane interactions with the lidocaine molecules. The 'sodium channel' spans the phospholipid bilayer on the membrane of the cell and is extremely narrow.  The anaesthetic binds much more tightly to the channel when charged due to electrostatic interactions, and so helps block the sodium channels and make the area temporarily numb[10].

For more serious circumstances, when a patient has to be completely unaware, doctors use general anaesthesia. This renders patients unconscious with no perception or memory of the surgery while it is happening. It also limits the physiological responses to invasive procedures and surgical cuts, keeping blood pressure, stress hormone release and heart rate constant during the operation.

General anaesthesia is still quite a mystery to the scientific world[11], as the biochemical mechanism which controls it is still speculated about. To induce unconsciousness, anaesthetics have different sites of action and affect the central nervous system at varying levels of severity. Common areas of the CNS whose functions are often interrupted or changed during general anaesthesia include the cerebral cortex, thalamus, and spinal cord.

Paul Ehrlich stated that drugs act only when they are bound to their receptors; however, this concept does not seem to apply in the case of general anaesthetics. There are two main reasons to support this concept:

·      

            The molecular structures of these anaesthetics are very simple and different to one another

, and so there is no obvious structure-activity relationship

      Most general anaesthetics have very weak affinities for their targets acting at much higher concentrations than most other drugs

In 2015, roughly 15 million operations and minor procedures were carried out in the UK alone, and this would never have been able to happen without anaesthetics.

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[1] http://www.nhs.uk/ipgmedia/national/Arthritis%20Research%20UK/Assets/Painkillers-analgesics.pdf

[2] http://www.arthritisresearchuk.org/arthritis-information/drugs/painkillers.aspx

[3] http://www.drugs.com/aspirin.html

[4] https://en.wikipedia.org/wiki/Aspirin

[5] https://en.wikipedia.org/wiki/History_of_aspirin#World_War_I_and_Bayer

[6] http://www.nhs.uk/Conditions/Anaesthesia/Pages/Introduction.aspx

[7] http://patient.info/doctor/practical-local-anaesthesia

[8] http://www.drugs.com/pro/lidocaine.html

[9] https://www.evidence.nhs.uk/formulary/bnf/current/15-anaesthesia/152-local-anaesthesia

[10] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2075196/

[11] https://www.newscientist.com/article/mg21228402-300-banishing-consciousness-the-mystery-of-anaesthesia/

The Use of Maths in Medicine

Maths is used every day in hospitals, surgeries and many more healthcare facilities around the world. As a prospective medical student, I wanted to know more about the huge role that this discipline plays in the world of medicine, and so I did some research and came up with the following conclusions.

One of the most basic and common use of maths in medicine is prescriptions and drug dosing. Most medications have guidelines for dosage amounts in mg/kg, and so doctors need to figure out how many milligrams of medication each patient will need, depending on their weight. There is a big role here for conversions, as sometimes patients will only know their weight in pounds or stone, and so this will have to be changed quickly by the doctor or nurse to the right units. This is extremely important as a wrong drug dosage could mean a life or death decision, especially if the drug being administered to the patient is especially potent and so could be toxic if given in high amounts, or if a patient is desperately in need of a drug, and not enough is given to that patient. Doctors must also determine how long a prescription will last, as this figure can be in days, weeks or months, and so healthcare professionals must be able to give the right amount of drug to a patient over a specific period of time, without the patient needing to come back as they don’t have enough of their medication.

Another important factor to consider is how long the medication needs to stay inside the patient.  This will determine how often the patient needs to take their medication in order to keep a sufficient amount of the medicine in the body. The amount of medicine in the body decreases by a certain amount in a specific time (e.g. 10%hour^-1), and this can be expressed as a rational number- 1/10. This rational constant creates a geometric sequence, as the amount decreases by a fixed ratio each time unit, and so doctors can use this concept to decide how often a patient needs to take their prescribed medication.

Another common use of maths in the medical field is for the calculation of one’s BMI, which is a number derived from an adults weight and height to judge whether they are of a healthy weight. This is a very common equation, used to test people’s weight all around the world, and shows that healthcare professionals have to be able to use equations with the right units; however, one’s BMI is not a very good indicator of healthy weight. I say this as, when you ‘plug’ weight into the equation to calculate a patient’s BMI, it doesn’t consider whether the weight is muscle or fat, and so a bodybuilder could be classified as ‘obese’ on the BMI scale even though they are healthy.

One of the more less-commonly known uses of maths in this field is through Extracorporeal Shockwave Lithotripsy, which is used to treat kidney and gallstones non-invasively. This technique is all thanks to the reflective properties of an ellipse, which can be seen in the diagram to the left. Shockwaves are generated at one focus and will reflect off the ellipse and pass through the second focus- creating a unique property which allows ESWL to take place. In order for the lithotripter to work, the patient’s stone must be at one focus point of the ellipsoid and the shockwave generator at the other focus.  The patient is then laid on the table and moved into position next to the lithotripter. Doctors then use a fluoroscopic x-ray machine to get a visual on the stone, allowing the focus to be at the precise location of the stone.  A water-filled cushion is then wrapped around the machine and rests on the patient’s side; this acts as a sort of buffer for the machine, as the water allows the shockwaves to travel through the body’s tissues safely because water and the soft tissue have the same density. The stone has a larger density and so is then shattered by the shockwaves. This is a popular choice for patients as it is quick, relatively safe and non-invasive, and so is available on the NHS.

In conclusion, mathematics plays a crucial role in medicine as it directly impacts people’s lives, and so it is very important for healthcare professionals to be very accurate in their mathematical calculations.

The Legacy of Elizabeth Blackwell

The World Health Organisation estimates there to be around 10-15 million practising doctors in the world; around 4-6 million of those being female. The figure is rapidly increasing, with estimates showing that females will soon outnumber male doctors towards 2017; however, this has not always been the case. Women have only been able to qualify as certified physicians as of the First World War, when doctors were desperately needed to take care of injured soldiers regardless of their gender, and one of the most influential women in this race for equality was Elizabeth Blackwell.

Born in Bristol in February 1821, Blackwell moved to the United States as a young girl with her family, where she first worked as a teacher, alongside her mother and two sisters. She had her so-called ‘eureka moment’ in her late-twenties, when Blackwell’s close friends was diagnosed with a terminal illness, and found it embarrassing to have male doctor. Compelled by a strong sense of compassion and determination, Blackwell then decided that she was going to peruse a career in medicine, although it was virtually impossible to achieve this feat. Her family told her it was a good idea, but unrealistic; it was too expensive, and such education was not available to women- yet Blackwell was strongly attracted to this challenge, and so applied to all the medical schools in New York and Philadelphia.

In 1847, she was then accepted into the Geneva Medical College after the male staff voted to let her join the university as a joke. As a determined young woman in an all-male medical school she was often humiliated by students, professors and patients alike; yet, she took this in her stride and graduated at the top of her class in 1849, after having written her thesis on Typhus fever.

She then worked as a physician in London and Paris, and her dreams of becoming a surgeon were shattered in 1851 when she contracted purulent opthalmia from a patient, leaving her blind in one eye.

However, after having encouraged many more women to become doctors, she opened a small dispensary in a rented room in New York, and this then further progressed into The New York Infirmary for Women and Children, which opened in 1857, with help from fellow female doctors Marie Zakrzewska and Emily Blackwell.  This institution and its medical school for women (which opened 1867) provided training and experience for women doctors and medical care for the poor, and is estimated to have helped at least 100,000 civilians in New York while it ran, and one of the alumni of the college (Sophia Jex-Blake) then returned to England and set up the first medical school especially for women in the UK.

In addition to this, at the outbreak of the American Civil War in 1861, she helped organize the Woman’s Central Association of Relief and the U.S. Sanitary Commission alongside President Abraham Lincoln, training nurses to help take care of injured soldiers in the war. After returning to England to continue her medical career in women’s medicine, she became the first woman to have her name placed on the British medical register, and published many papers and books, with some examples being: The Religion of Health (1871), Essays in Medical Sociology (1902) and most famously her autobiography- Pioneer Work in Opening the Medical Profession to Women (1895), in which she elaborately records her struggles and triumphs which she went through in being one of the first officially recognized female doctors in the world.

Blackwell showed the scientific world that women were just as capable of becoming eminent physicians as men, and in turn inspired a huge revolution of women in medicine and other scientific careers. It was from her inspiration and perseverance that we owe many female-specialized hospitals and health centres today, and in the words of the heroine herself: “If society will not admit of woman's free development, then society must be remodelled”.

The Junior Doctor Strike: What You Need To Know

In the last few months junior doctors all over the UK have been heavily objecting the proposed changes to the junior doctor contract proposed by the government, which has led to a 24-hour strike of over 90% of the UK's junior doctors, leaving the NHS in a state of distress.

This opposition has arisen as the government has decided that the current contracts are ‘unfair’ and too old-fashioned, and even though the initial plans for a new contract were first drawn up in 2012, talks only started breaking down in 2014. The government has indicated it will impose the new contract in England and the British Medical Association (BMA) has responded by initiating the industrial action process.

So, what exactly is a ‘junior doctor’? The term ‘junior doctor’ refers to doctors which have just graduated from medical school up to doctors which have had up to 10 years’ worth of experience being a fully qualified doctor- to most people a 32-year old hospital specialist would seem to be a ‘senior’ and well-qualified doctor. The starting salary for a junior doctor is currently just under £23,000 a year, but with additional payments for extra services such as unsociable hours, this can quite easily top £30,000.

Junior doctors at the top end of the spectrum can earn just over £70,000 per year. However, it's important to remember these doctors often make life-and-death decisions and carry out surgery, in addition to having over 10 years’ worth of professional experience as a qualified doctor.

Given that 1/3 of all doctors in England are junior doctors, this contract change will directly affect around 55,000 doctors, making it a lot harder so earn more money and work healthy hours.

The proposed changes to the contract will change the standard working hours for junior doctors in England, which are currently set at 0700-1900 Monday-Friday, which is already quite long and is certainly a strain on the NHS. What the new contract proposes is that these standard hours would change to 0700-2200 Monday-Friday in addition to 0700-1900 on a Saturday- which is, in my opinion, quite ridiculous as this implies that working on 0800 on a Monday morning is the same as working on a 1900 on a Saturday evening.  As the standard number of hours has increased, it means that junior doctors will have to work practically all week to earn a decent pay for the first few years or their careers.

Another problem which will almost certainly arise is extreme tiredness and fatigue, which is already a problem within much of the NHS and will be made even more common with these new changes. With this proposed change, therefore, comes the question of patient safety, as it has been proven that doctors make more mistakes practicing medicine whilst being tired than drunk, which ultimately poses the question: to what extent would you be comfortable with an exhausted surgeon operating you who is more likely to make a mistake than a surgeon under the influence of alcohol?

The main problem the government is trying to solve here is timings: in an ideal world, they would like to see a 24/7 NHS which everyone has complete access to; however, they are trying to do this without spending huge amounts of money by employing more doctors, and so, there is only one foreseeable solution without spending huge amounts of money- to stretch the capacity of NHS doctors.

Personally, as a prospective medical student I think that this change in contract has very few proper advantages, as, even if we have a fully running 24/7 NHS, what is the point if barely any of the doctors are working to their full potential and putting the lives of thousands of patients at risk every day?

Should we ban smoking?

Smoking tobacco is the most expensive social burden in the UK, costing the government roughly £65 billion per year. It also indirectly accounts for up to 20% of deaths in the UK, as it is the main causing factor of lung cancer and smoker's illnesses, such as chronic bronchitis and emphysema. Despite 65% of regular smokers dying from some form of respiratory disease, 20% of the English adult population still smoke; causing huge strains on both a personal and national scale, which raises the question: should we ban smoking?

The reasons for the ban of smoking are pretty simple if you think about it: increased life expectancy, quality of life and a less-stressed NHS. On average, the life expectancy of a smoker is roughly 5-10 years lower than a non-smoker, and in addition to this the DALYs (disability-adjusted life years) of smokers can add up to around 15 years- about 1/5 the average life. Furthermore, 1/3 of cigarettes in Britain are smoked by people with mental illnesses, seriously worsening their physical health, in addition to their mental issues. 

COPDs (Chronic obstructive pulmonary diseases) are found in around 58% of smokers, and this includes diseases such as chronic bronchitis, emphysema and lung cancer; the former two of which cause permanent and irreversible lung damage. Emphysema is a condition in which the phagocytes in the blood move to the inflamed lung tissue when smoking and release the enzyme elastase (in order to reduce swelling), which then digests the walls of alveoli- therefore reducing their surface area, meaning that gas exchange happens less efficiently and so people who have this often have to have a constant flow of oxygen going into their blood stream (often an oxygen tube) so that their body has enough oxygen to function. 

In addition to this, countries where tobacco is farmed are extremely poor, and often the average worker on tobacco farms is a child. This is the case in Malawi, where almost all of the workers have gained a nicotine addiction from handling the tobacco leaves every day, but they are often forced to carry on as, for many, this is their only source of income (this often results in nicotine poisoning). Furthermore, there are also many environmental impacts which tobacco farming has, including deforestation, of which 26% is due to tobacco farming in Malawi. 

In conclusion, there are simply no advantages of smoking tobacco - apart from the social factor of thinking its 'cool'-, so why not just ban it? Well, its not as simple as that.

Many people argue that every human being has the right to do what they want with their own body- which I partially agree with, as I think that one's body is truly one's own; however, I think that if one is harming themselves or the people around them this belief is partially compromised. This belief is applicable to not only smoking but a huge range of other medical issues and diseases, such as obesity, substance abuse and alcoholism, and, such as with many other ethical issues surrounding medicine, there is no prefect solution to this problem.

As with any other damaging burden, the government and the NHS are trying to persuade people to stop and try to live a healthy lifestyle, however I don't think that there will ever be a complete ban on smoking due to the belief that everyone can do what they want with their body; but, I do think that this raises questions such as: why is prostitution illegal if everyone can do what they want with their own body?

In a nutshell, theoretically a ban on smoking would do more good than bad, as it would improve millions of lives across the UK, but due to ethical issues it is simply not feasible in the real world that we live in.

To run or not to run?

Ultramarathons; the ultimate endurance test on the human body, but are they really worth it?

Ultramarathons are classed as races which are longer than the standard 26 mile Marathon, and can be of of a variation of distance, terrain and timescale- for example they can range from about a 5 hour race to a 64 day one.
There are huge benefits which the super-human runners gain from, ranging from joint health to an increased sex appeal, but is the huge amount of stress on their bodies really worth the effort?

Researchers at the hospital of the University of Ulm in Germany followed a group of 44 runners who competed in the 2009 Trans Europe Foot Race. Lasting 64 days, the athletes ran nearly 2800 miles from southern Italy to Norway and scientists regularly tracked their physiological health during the spectacular event. They took a portable MRI scanner with them, and so periodically scanned the runners' legs, feet, heart, brains and cardiovascular systems every 3-4 days, in addition to taking blood and urine samples.

Uwe Schütz, the leader of the team of researchers, and his colleagues also measured the amount water emitted by the shock-absorbing cartilage between the bones of the leg, around the knee and ankle. They found that, during the first 1550 miles of the race, all 44 runners experienced some cartalige degradation at some point in the beginning of the race. However, after this point the cartilage seemed to auto-regenerate as the athletes continued on. This has thus proven for the first time that cartilage does not have to be at rest to regenerate, as before the study scientists thought that it needed to renew itself in order to get better.

Futhermore, organs such as the brain were also negatively affected by the huge feat of human endurance, as, in 13 of the participatants who agreed to extra brain scanning, the brain seemed to decrease in volume by up too 6%. This loss was in grey matter, but as the sample size was so small and particular, it is hard to judge whether this is the general case, as the sample is not specifically representative of the population. However, there were no lasting effects on participants as the brain seemed to regenerate also and return back to its normal size.

There are many theories as to why this happens, including one which suggests that this is due to a lack of visual stimulation during the 64 days, as one of the main regions of matter loss in the brain is particularly known to be involved in visual processing. Other theories include general fatigue, exhaustion and extreme levels of physical activity.

In a nutshell, there are still many unknowns regarding the physical effects of running particularly long distances; however, I think that the positives highly outweigh the negatives, as all of the physiological effects in this study seemed to dissapear within 6 months, and with obesity being one of the highest indirect causes of death in the world, I think it is better to be more active than not.

Lithium: The Element of the Future

The salar de Uyuni is the biggest salt flat in the world and lies in the heart of southern America, next to the Bolivian Andes- it stretches 100km across at an altitude of 3600m, and holds the largest reserve of lithium in the world.
 

The flat holds around 1/3 of all lithium on the planet, and this is due to the aridity of the area- leaving surface water to be baked by the sun, causing high levels of evaporation, and therefore creating a mineral-rich brine that flows under the salt desert’s crusty surface.  In addition to this, magma currents which are high in lithium are also aiding the vast natural abundance of the element, creating a geologically unique lithium resource, which in the future could power most of the transportation in the world.
 

The main method of extraction:

·         Drill into the lithium-concentrated brine channels 50m beneath the surface which is very quick but expensive

·         Place the brine into evaporation pools, where the sun evaporates the water and makes a concentrated lithium salt- cheap but slow, works at 7mm/day

Lithium has significant global interest now, as there are huge plans to use it for a less harmful energy resource than fossil fuels. This change happened in 1991, when Sony released the first ever portable gadget powered by a lithium-ion battery. This has obviously now expanded to smartphones, laptops, cameras etc, pretty much all of our handheld devices.

 

Lithium is used for these batteries as it is the lightest metal, with only 3 protons per atom, making it easy to use as a small battery which can be used in gadgets.

Other uses of lithium include medicine; world’s leading treatment for bipolar (manic depression) uses a form of purified lithium carbonate.

However, the biggest demand of lithium at the moment is from the transportation industry- for electric cars. This is due to popular hybrid cars, which use lithium batteries, and this element is even more useful as, in its pure form, it has a similar energy density to diesel fuel.

It is important that the Bolivian government and other authorities do not exploit this natural resource as it needs to be extracted using sustainable methods to ensure that we are not compromising the abilities of  future generations to extract and use this vital element for renewable energy etc.

Carolina Valensise 04/12/15