The technology involved in genetic editing has made huge breakthroughs in the past few years. What began as an unrealistically difficult and ambitious endeavour in the increasingly complex world of medicine has now manifested into a reality through technology such as CRISPR. Genetic editing holds the power to not only treat but prevent countless diseases, transforming the world of medicine and possibly even diverging the path of human evolution itself.
The debate as to whether genetic editing is justified has been fiercely battled for years. The first genetically edited babies were born in China in November 2018. The scientist responsible for this, He Jiankui, was found guilty of “illegal medical practices”. He served three years in prison and was fined a huge 3 million yuan (£327,360). The Chinese court even insisted Jiankui “crossed the bottom line of ethics in scientific research and medical ethics.” Large numbers of people agree with this claim, arguing genetic editing can never be justified.
The main reasons supporting this argument include how genetic editing involves humans ‘playing God’. Religious believers often insist that only God should have the right to edit such a crucial element of our individuality, and humans should be happy with their genetic identity as it is ‘God’s gift’, even if this genetic identity involves a disease.
The misuse of genetic editing has been a cause of much concern. Its potential use to enhance characteristics such as physical strength, looks, or even intelligence would be unfair to ‘unedited humans’ and possibly biased to the wealthy- the poor will likely be unable to afford genetic editing. A ‘black market’ related to gene editing - much like ‘back alley ’abortions - may develop, where those who cannot afford gene editing will choose unauthorised and unregulated facilities with likely higher complication rates due to the lack of sanitation and doctors able to preform the procedure.
Furthermore, if everyone decides to genetically edit themselves there would be a reduction in genetic variation in the human species. Further concern is that eradicating genetic diseases would result in overpopulation, thus greatly contributing to the ever worsening issues of global warming and depletion of essential natural resources.
There is also a strong ethical issue associated with all types of gene editing – is it really correct for people to use the system to ‘customise’ their own children? Surely only the child should have the right to alter their appearance and should do it when they are old enough to understand the significance of this irreversible decision.
Genetic editing may gives rise to eugenics in dictatorship countries - where political or government groups forcefully try to modify the gene pool of some of their subjects. This may be to ensure mental and physical advantage in warfare or scientific careers.
In addition to ethical issues and the potential misuse of genome editing, there are concerns over safety and possible complications. Germline therapy (a type of genetic editing where DNA is transferred into the cells that produce reproductive cells) poses a potential infection risk through the use of viral vectors that enable DNA to be transferred into these cells. No one can truly predict how these resulting genes may interact during fertilisation and what genetic defects may arise.
On the other hand, one can argue that genetic editing can easily be justified. After all, a long time ago surgery would have been considered as a human taking the opportunity to ‘play God’. Surgery was previously extremely risky due poor hygiene, little access to powerful anaesthetic and sub-optimal techniques with high complication rates. However, surgery is currently much safer- millions of people undergo it and change their lives for the better. Many people predict this future for gene editing – there is nothing wrong with people wanting to rid themselves of a disease to empower themselves and become healthy again- we all have the right to be as healthy as possible. Nature can be very cruel to us- people cannot choose whether they end up with genetically inherited diseases such as haemophilia which completely destroy one’s life and damage their mental health as well as their physical health. If research in genetic editing continues we will have the power to live long and happy lives. Couples can be reassured that their unborn children can too since germline therapy ensures the disease will not be inherited in the family again.
If gene editing becomes widespread and advanced enough it will be the key to controlling human evolution – humans will eventually be much more intelligent creatures who are more mentally and physically resilient to the variety of challenges life brings in our day to day lives. In fact, instead of waiting hundreds of thousands of years for beneficial mutations to arise (as with natural selection), we could start to see beneficial changes every year. Many people regard gene therapy as unsafe, however, as with all new therapies, medicine, and vaccinations, genetic editing will be vigorously tested and researched before it is released to the public as a standard procedure, certifying its safety.
In conclusion, genetic editing could greatly benefit people, increase longevity, and change the scale of human happiness and productivity by multiple orders of magnitude. It could eliminate thousands of diseases and many forms of pain and anxiety arising from them. There are only a handful of areas of research in the world with this much potential. However, whilst it may be a wonderful addition to medical science, there needs to be firm monitoring to ensure genetic editing is as risk free as possible. Furthermore, it must be strictly controlled to avoid misuse. Genetic editing has risks- we must proceed with caution, but many new technologies have risks and we are eventually able to use them to greatly benefit people throughout the world. We should not let fear hold back progress on this extremely promising new area of research.
By Lana, 11N
There is ‘liminal space’ between cellular life and death. Despite the fact that they are often thought of as oxymoronic, it is not as straightforward. Many have grappled to denote the moment of death for humans: Is it when the beating of the heart no longer occurs? When breathing stops? A lack of detectable activity? Divergent answers arise as death is a process, and by definition, not an irreversible one.
In regard to cells, predominantly it is assumed that once the cells pass critical checkpoints, the death process is irrevocable. Such checkpoints include condensation of nucleus, collapse of DNA, disintegration of the mitochondria and cell shrinkage. Moreover, these events are often intentional. An essential component of life is programmed cell death, with over 20 forms proposed. Among these, apoptosis is the most notable and well-studied due to its regulatory mechanisms in cell suicide, and crucial roles in embryonic development, maintaining a balance of cellular multiplication and regulating internal conditions (homeostasis) by eradicating the undesired, faulty or dangerous cells in the body.
Apoptosis in Greek is defined as ‘falling’ and it expedites the habitual turnover of cells, analogous to leaves falling from a tree in autumn. A number of triggers are involved in apoptosis, but at length they activate a decisive group of ‘executioner’ proteins named caspases. These enzymes, by cleaving hundreds of various types of proteins within a cell, inflict destruction in cellular targets, attack structural proteins and deconstruct the cytoskeleton, resulting in cell shrinkage to blebs and die.
With all this, dubiety also follows. The fence which segregates life and death is porous even at the degree of cells (the rudimentary units of life). A growing body of evidence have recently demonstrated that cells that are believed to be dead or terminal are able to revive themselves, or somewhat revive, hence reverse apoptosis when under the right conditions. This phenomenon is referred to as anastasis (Greek for ‘rising to life’) and can occur in vitro and in vivo.
A significant role that anastasis plays involves the maintenance of differentiated cells that are difficult to recoup, such as neurons and cardiomyocytes. In this way, anastasis can counter many of the complications resulted by apoptosis. A variety of degenerative diseases, such as Alzheimer and Parkinson, are associated with apoptosis not functioning correctly. This is because protein aggregation can activate an enzyme that triggers apoptosis, resulting in the death of neurons and loss of brain function.
However, if we rival apoptosis to the demolition of buildings, the detrimental effects that arise when anastasis takes place can be also understood. The caspases involved in the breakdown of cellular structures are somewhat like demolition workers destroying buildings. If someone decides after: “I don’t want it to be destroyed, please rebuild it.” Then, the damage has to be repaired, but this process of restoring may go wrong. You won’t have a complete replica of the original. Therefore, when anastasis takes place, the resurrected cells may bear chromosomal abnormalities and acquire mutations. This will engender a multiplier effect where particular mutations will cause unchecked cell growth and proliferation. Henceforth, this revival process may trigger normal cells to become carcinogenic, by gaining new mutations and transmuting into more hostile and metastatic cancers. In this way, cancer cells are said to employ anastasis as a way to ‘cheat death’ and use it as an escape tactic to survive cell- death- inducing anti-cancer therapy (e.g. chemotherapy and radiotherapy).
The correlation between anastasis and cell regeneration, rise of disorders and cell death decision is yet to be elucidated, as additional research is required to confirm a direct link. Ultimately, if there truly is a correlation, the resurrection of cells could increase awareness into multidisciplinary fields of science that supplement our understanding in the control of cell survival and destruction. Furthermore, it could provide insight into identifying novel analeptic approaches for brain damage, cancer, injury to tissue and moreover regeneration medicine by meditating the reversibility of apoptosis.
1. Kroemer G, et al. 2009. Classification of cell death: recommendations of the Nomenclature Committee on Cell Death 2009
2. Jacobson MD, Weil M, Raff MC. 1997. Programmed cell death in animal development.
3. Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P. 2002. The cell cycle and programmed cell death.
4. Burke PJ. 2017. Mitochondria, bioenergetics and apoptosis in cancer.
5. Tang HL, et al. 2012. Cell survival, DNA damage, and oncogenic transformation after a transient and reversible apoptotic response.
6. Tang HL, Yuen KL, Tang HM, Fung MC. 2009. Reversibility of apoptosis in cancer cells.
7. Taylor RC, Cullen SP, Martin SJ. 2008. Apoptosis: controlled demolition at the cellular level.
8. Kerr JF, Wyllie AH, Currie AR. Apoptosis: a basic biological phenomenon with wide-ranging implications in tissue kinetics.
9. Sun G, Guzman E, Balasanyan V, Conner CM, Wong K, Zhou HR, et al. A molecular signature for anastasis, recovery from the brink of apoptotic cell death
10. Tang HL, Tang HM, Fung MC, Hardwick JM. In vivo Caspase Tracker biosensor system for detecting anastasis and non-apoptotic caspase activity.
11. Baskar R, Lee KA, Yeo R, Yeoh K-W. Cancer and radiation therapy: current advances and future directions.
By Gaya, Year 11
As a second patient is seemingly cured of HIV after receiving a stem-cell treatment for his (Hodgkin lymphoma) cancer, it begs the question of whether HIV is ‘incurable,’ as we have always assumed. This article will endeavour to explain how HIV and AIDS affect the human body, how Adam Castillejo was ‘cured’, and what all this means for the future of modern medicine.
HIV stands for the human immunodeficiency virus. It is a virus that attacks cells that would normally help the body fight infection (CD4 helper cells), making a person more vulnerable to other infections and diseases. CD4 helper cells are a subset of white blood cells that do not neutralise infections, but rather trigger the body’s response to infections.
There are 7 steps that HIV follows to multiply in the body. These are illustrated in the picture below. The process begins when HIV encounters a CD4 cell. The 7 steps in the HIV life cycle are
Not only does HIV attack CD4 cells, but it also uses the cells to make more of the virus. HIV destroys CD4 cells by using their replication machinery to create new copies of the virus. This ultimately causes the CD4 cells to swell and burst. Once the virus has destroyed a certain number of CD4 cells and the count drops below 200, a person will have progressed to AIDS.
You can get or transmit HIV through specific activities only. Most commonly, people get or transmit HIV through sexual behaviours and needle or syringe use. Only certain fluids- blood, semen, rectal fluids, vaginal fluids, and breast milk- from a person who has HIV can transmit HIV. It can also be transmitted from mother to baby during pregnancy via the placenta.
AIDS is the acquired immune deficiency syndrome. It is the name used to describe a number of potentially life-threatening infections and illnesses that happen when your immune system has been severely damaged by the HIV virus. Many people often confuse HIV and AIDS- HIV causes AIDS. HIV destroys CD4 T cells- white blood cells that play a significant role in helping your body fight disease. The fewer CD4 T cells you have, the weaker your immune system becomes. You can have an HIV infection, with few or no symptoms, for years before it turns into AIDS. AIDS is diagnosed when the CD4 T cell count falls below 200, or if you have an AIDS-defining complication, such as a serious infection or cancer. Thanks to better antiviral treatments, most people with HIV today don’t develop AIDS. Untreated, HIV typically turns into AIDS in about 8-10 years. AIDS only occurs once your immune system has been severely damaged and as mentioned before, is only diagnosed once the CD4 T cell count falls below 200, or if you have an AIDS-defining complication.
Antiretroviral medicines are normally used to treat HIV. They work by stopping the virus replicating in the body, allowing the immune system to repair itself and preventing further damage. These come in the form of tablets, which need to be taken every day. HIV is able to develop resistance to a single HIV medicine very easily, but taking a combination of different medicines makes this much less likely. On top of this, there are some people who are actually naturally resistant to HIV. CCR5 is the most commonly used receptor by HIV-1- the virus strain of HIV that dominates around the world- to enter cells. But a small number of people who are resistant to HIV have two mutated copies of the CCR5 receptor. This means the virus cannot penetrate cells in the body it normally infects. Researchers say it may be possible to use gene therapy to target the CCR5 receptor in people with HIV. Adam Castillejo was the second patient to be cured of HIV. He received a stem-cell treatment for a cancer (Hodgkin lymphoma) he had, and this rendered him virus-free. This is because the donor of the stem cells had the uncommon gene that gives them and now Mr Castillejo protection against HIV.
In order to understand how the phenomenon of Mr Castillejo becoming HIV free came about, it is important to look more closely at how stem cells work. Stem cells are special human cells that have the ability to develop (differentiate) into many different cell types, from muscle cells to brain cells. In some cases, they also have the ability to repair damaged tissues. Stem cells are divided into two main forms- embryonic stem cells and adult stem cells. The embryonic stem cells used in research today come from unused embryos resulting from an in vitro fertilisation procedure that are donated to science. These embryonic stem cells are pluripotent, meaning they can turn into more than one type of cell.
There are two types of adult stem cells. One type comes from fully developed tissues, like the brain, skin, and bone marrow. There are only small numbers of stem cells in these tissues, and they are more likely to generate only certain types of cells. For example, a stem cell derived from the kidney will only generate more kidney cells. The second type is induced pluripotent stem cells. These are adult stem cells that have been manipulated in a lab to take on the pluripotent characteristics of embryonic stem cells. Although induced pluripotent stem cells don’t appear to be clinically different from embryonic stem cells, scientists have not yet found one that can develop every kind of cell and tissue.
The only stem cell currently used to treat disease are hematopoietic stem cells- the blood cell-forming adult stem cells found in the bone marrow.
Stem cell transplants are used currently in the treatment of cancer. In a typical stem cell transplant for cancer very high doses of chemotherapy are used, sometimes along with radiation therapy, to try to kill all the cancer cells. This treatment also kills the stem cells in the bone marrow. Soon after treatment, stem cells are given to replace those that were destroyed. These stem cells are given into a vein, much like a blood transfusion. Over time, they settle in the bone marrow and begin to grow and make healthy blood cells. This process is called engraftment.
There are two main types of stem cell transplants.
Autologous stem cell transplants are when the stem cells come from the same person who will get the transplant. In this type of transplant, your own stem cells are removed, or harvested, from your blood before you get treatment that destroys them. Your stem cells are removed from either your bone marrow or your blood, and then frozen. After you get high doses of therapy, the stem cells are thawed and given back to you. One advantage of autologous stem cell transplant is that you’re getting your own cells back. You do not have to worry about the new stem cells (engrafted cells) attacking your body, or about getting a new infection from another person. But there can still be graft failure, which means the cells don’t go into the bone marrow and make blood cells like they should. A disadvantage of an autologous transplant is that cancer cells may be collected along with the stem cells, and later put back into your body. Another disadvantage is that your immune system is still the same as it was before the transplant. As the cancer cells were able to escape attack from your immune system before, they may be able to do so again. To help prevent this, some places treat the stem cells before giving them back to the patient to try to kill any remaining cancer cells- this is called purging. Again, this has problems because some normal stem cells can be lost during this process. This may cause your body to take longer to start making normal blood cells, and you might have very low and unsafe levels of white blood cells or platelets for a longer time, increasing risk of infections or bleeding problems.
Allogeneic stem cell transplants are when the stem cells come from a matched related or unrelated donor. In the most common type of allogeneic transplant, the stem cells come from a donor whose tissue type closely matches the patient’s. Blood taken from the placenta and umbilical cord of new-borns is a newer source of stem cells for allogeneic transplant. Called cord blood, this small volume of blood has a high number of stem cells that tend to multiply quickly. But the small volume normally does not contain enough stem cells for large adults, so is mostly used for children and smaller adults. A positive to this type of stem cell treatment is that the donor stem cells make their own immune cells, which could help kill any cancer cells that remain after high-dose treatment. This is called the graft-versus-cancer effect. Also, the donor can often be asked to donate more stem cells or even white blood cells if needed, and stem cells from healthy donors are cancer-free. Cons- the transplant might not take; the transplanted donor stem cells could die or be destroyed by the patient’s body before settling in the bone marrow. Also, the immune cells from the donor may not just attack the cancer cells- they could attack healthy cells in the patient’s body. This is called the graft-versus-host disease. There is also a very small risk of certain infections from the donor cells, but as donors are tested before they donate, this is rare. A higher risk comes from infections you had previously, and which your immune system has had under control. These infections may surface after allogeneic transplant because your immune system is suppressed by medicines called immunosuppressive drugs. Such infections could cause serious problems, if not death.
Of course, this all brings up the question of why can we not use stem cell transplants to cure all HIV patients? The answer is that it would not be possible to find enough genetically matched bone marrow donors with the naturally occurring genetic mutation to treat the 33 million people with HIV, even if that was desirable, safe and ethical. Also, most people with HIV already have very compromised immune systems, and so carrying out stem cell transplants would carry a significant risk, which may not be outweighed by the benefits.
A lot of research has gone into the potential of using gene therapy for treating and preventing diseases in general, and specifically for HIV. Gene therapy is an experimental technique that uses genes to treat or prevent disease. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery. There is research into several approaches to gene therapy, including:
- Replacing a mutated gene that causes disease with a healthy copy of the gene.
- Inactivating, or ‘knocking out’ a mutated gene that is functioning improperly and causing unwanted consequences.
- Introducing a new gene into the body to help fight a disease.
Gene therapy is a promising treatment option for a number of diseases, including inherited genetic disorders, some types of cancer, and certain viral infections. However, the technique is risky and is still under study to make sure that it will be safe and effective. Gene therapy is currently being tested only for diseases that have no other cures.
Gene therapy is promising in helping cure HIV because people who are naturally resistant to HIV have two copies of the CCR5 receptor due to a random mutation. Gene therapy could be used to give people the second mutated copy of this receptor if they target the CCR5 receptor, hence, curing people of HIV. However, gene therapy is still a controversial technique, and whilst many believe that it will become a staple of 21st century medicine, experts say society will be better served if medical researchers proceed slowly and prudently. Therefore, it is likely to be decades until gene therapy becomes normalised in modern medicine. And for specific treatments, such as this supposed HIV cure, many years of testing, clinical trials and waiting for approval would have to pass before the treatment becomes available.
Kiran Kuri, Year 13
‘A mutation is a change in the DNA at a particular locus in an organism.’ Mutation plays an important role in evolution and is the ultimate source of all genetic variation. It is salient as the introductory step of evolution because it creates a new DNA sequence for a particular gene, creating a new allele. Gene mutations occur very rarely but its rate can be artificially increased by mutagenic agents such as mustard gas, x-rays and ultraviolet light to give induced mutations.
Genetic mutations can be classified in two major ways: hereditary and somatic. Hereditary mutations are present virtually in every cell in the body and are inherited from a parent. Due to their presence in the parent’s gametes, the mutations are also referred to as germline mutations. If a mutant gene is passed onto offspring, when growth occurs due to mitosis, the mutation will be present in all cells. The other type of mutations is somatic (acquired). These occur during a person’s life and are therefore present only in some cells. These can be caused by environmental factors such as ultraviolet radiation from the sun, or due to an error made during cell division, which is called non-disjunction. Somatic mutations cannot be passed to offspring due to the mutations not being present in gametes.
A number of regions of DNA possess dominance determining when and where genes are turned ‘on.’ Occurring mutations in these parts of the genome can substantially change the way the organism is built; a mutation in a control gene can cause a cascade of effects in the behaviour of genes under its control. An example of a control gene is hox genes. They are found in a number of animals like humans and designate where the head goes and which regions of the body grow appendages. Such genes assist in the directing of the body’s unit construction eg. segments, limbs, and eyes. Thus evolving an extensive change in basic body layout may not be so unlikely; it may simply require a change in a Hox gene and the favour of natural selection.
‘Mutations can be either beneficial, neutral, or harmful for the organism.’ Though it is said that factors in the environment an influence on the rate of mutation, they are not thought to influence the direction of mutation. This means that exposure to harmful chemicals may increase the mutation rate, but will not cause more mutations that make the organism resistant to those chemicals. In this respect, whether a certain mutation occurs or not is unallied to how serviceable that mutation would be, proving the concept that mutations are random. For example, in the U.S. where people have access to shampoos with chemicals that kill lice, a lot of lice that are resistant to those chemicals are commonly encountered. Two possible explanations can arise for this:
‘HYPOTHESIS A - Resistant strains of lice were always there — and are just more frequent now because all the non-resistant lice died.
HYPOTHESIS B - Exposure to lice shampoo actually caused mutations for resistance to the shampoo.
In 1952, Esther and Joshua Lederberg performed an experiment that aided in showing that mutations are random. They focused on the idea that bacteria grow into isolated colonies on plates. These colonies have the ability to reproduce from an original plate to a new plate by the process of ‘stamping’ (stamping the original plate with a cloth and then stamping empty plates with the same cloth). Bacteria from each colony are picked up on the cloth and then deposited on new plates. This led to Esther and Joshua hypothesising that antibiotic resistant strains of bacteria surviving an application of antibiotics had the resistance before their exposure to the antibiotics, not as a result of the exposure. Their experimental set up is summarised below:
This shows that before the encounter of penicillin the resistant bacteria were present in the population thus did not evolve resistance in response to the exposure of the antibiotic. Moreover, from the evidence available, we can hence deduce that mutations might therefore preferentially form around existing ones.
By Gaya Giritharan, 10F
CN: picture of brain surgery
How do brain tumours form?
A brain tumour occurs when brain cells divide and grow in an abnormal and uncontrolled way. When a cell divides, it copies its genes and replicates itself. Sometimes however, mistakes occur in this process, and are known as mutations. Whilst some mutations are harmless, others cause the cell to divide uncontrollably.
The mutation causes the cells to behave as though they are receiving a growth signal or deactivates the checkpoints that would stop the cells from dividing. Therefore, the cells continue to divide uncontrollably, forming a tumour
What is glioblastoma?
Glioblastomas are the most common and aggressive type of brain cancer that forms from cells called astrocytes in the nervous system. They belong to a group of brain tumours called gliomas, which are malignant tumours of the glial tissue. The average age of patients with glioblastoma is 64 years old; its risk increases with age. Whilst glioblastomas are mostly found in the cerebral hemispheres, they can be found anywhere in the brain.
Glioblastoma is a ‘diffuse’ tumour, meaning they are infiltrate and able to spread into healthy tissue in other parts of the brain, and therefore is very fast growing and fast spreading. This makes it very difficult to pinpoint precisely where the tumour starts and ends. Particularly aggressive glioblastoma are able to even spread to the opposite side of the brain through connection fibres, known as corpus callosum. Gliobastoma’s ‘diffuse’ property is particularly problematic when tumours spread near to important regions of the brain that are essential to functions such as movement and coordination.
Symptoms and side effects of glioblastoma
Due to mass swelling from the fluid surrounding the glioblastoma (edema), patients develop symptoms very quickly. The most common symptoms are nausea, vomiting and severe headaches, and are predominantly due to the increased pressure in the brain as a result of the tumour and swelling. Neurological symptoms are also not uncommon, for example, weakness, sensory changes, difficulties with balance, and neurocognitive or memory issues.
Treatment of glioblastoma
Mark Gilbert, director of the Neuro-Oncology Branch in NCI’S Centre for Cancer Research said, “Glioblastoma is one of the hardest to treat in the history of oncology.” Despite continued efforts to develop promising treatments for glioblastoma, none have proved successful, with only 3.3% of patients living for longer than 2 years. The usual treatment for patients with glioblastoma is a surgery to remove most of the tumour, followed by chemotherapy and radiation.
Commonly, surgery would take place in an attempt to remove as much of the tumour as possible- a procedure known as debulking. It is difficult to remove the entire tumour because glioblastoma is a diffuse tumour, which means it can spread into the rest of the unaffected brain, and so it is difficult to tell the difference between affected and unaffected brain tissue.
There have been recent advances, which have improved the extent to which the tumours can be removed in surgery. Prior to surgery, patients are given a drink containing the substance 5-ALA, which causes the affected cells to glow pink under violet light. This makes it less difficult to tell the affected and unaffected cells apart, and so more of the tumour can be removed.
Surgery is also used for palliative treatment in cases where the tumour cannot be removed- intracranial pressure is reduced to relieve symptoms.
Radiation involves the use of high precision high-energy beams, for example X-rays, gamma rays or protons, to kill the affected cancer cells. An immobilization mask is worn by the patient to hold their head in the same position and limit movement. Intensity-modulated radiation therapy is an advanced mode of radiotherapy that uses computer-controlled liner accelerators to deliver precise radiation doses to a malignant tumour. It allows for the radiation dose to conform more precisely to the 3D shape of the tumour by controlling the intensity of the beam in small volumes. The treatment is planned specific to the tumour using the CT and MRI images of the tumour in conjunction with computerized dose calculations to determine the dose intensity pattern that is best suited for the tumour.
Chemotherapy is a technique that uses cytotoxic drugs to kill the affected cancer cells. Temozolomide, Iomustine and carmustine are the most commonly used drugs in chemotherapy. Temozolomide works by preventing the tumour cells from making new DNA, which prevents them from making new cells and therefore growing. It also makes the affected cells more sensitive to radiation, so chemotherapy and radiation treatments are often used together. Whilst radiation acts on the affected tumour cells, chemotherapy acts on all dividing cells, but healthy cells are able to repair themselves easier than the tumour cells, so few healthy cells die after treatment. The various ways in which chemotherapy can be given are:
Tablets- chemotherapy drugs can be taken in tablet form and are absorbed and carried around the body in the bloodstream to reach the affected tumour cells.
Injection/drip- chemotherapy drugs can be injected into a vein or into the spinal fluid. A drip may be used to insert the drug into the bloodstream, where it is absorbed and carried around the body to the affected cells.
Wafers- drugs can be put inside a polymer wafer and inserted into the brain during surgery. The wafers are made of a biodegradable material so they can dissolve over a few weeks, releasing the drug into the brain to kill the tumour cells.
Whilst several immunotherapy-based treatments have proved unsuccessful in facing glioblastoma, vaccinations has been considered to be one of the more promising approaches.
A particular advance in the use of vaccines for glioblastoma was made by Dr Jason Adhikaree from the University of Nottingham, who proposes to use dendritic cells, a type of white blood cell, to create the vaccine. The dendritic cells would be taken from the patient’s body and ‘taught’ to recognise and kill the glioblastoma-affected cells. They will then be injected back into the patient’s body, in which they can attack the tumour cells.
By Maheria Rashid
It was in India in 2013, that dolphins gained the status of “non-human persons.” To most, it was entirely unprecedented to see dolphins receiving their own ‘dolphin rights’, as it were. This provoked greater research into dolphin behaviour and psychology, to determine whether dolphins do in fact share the same traits as humans, enough to render them ‘people’.
It was discovered that they did, to an alarming degree. Dolphins were found to recognise themselves in a mirror experience emotion; have individual personalities, and understand complex gestures made by humans. It was further acknowledged that Dolphins could understand sign language words, and interpret the syntax of language, a trait highly suggestive of intelligence. They could recall events and change their behaviour as a result of previous experiences, and they could use echolocation to detect objects over 70 metres away. Cognitive psychologist, Diana Reiss even suggested that dolphins could “learn to poke an underwater keyboard to request toys to play with.” She further declared that parallels could be drawn between the learning capabilities in small children and dolphins. So, if dolphins are intelligent enough to be classified as people, how do their brains differ from other animals?
To answer that, we must turn to the evolutionary paths of both dolphins and other species. The last common ancestor of humans and monkeys existed roughly six million years ago. In contrast, Cetaceans (the collective name for dolphins, whales and porpoises) diverged from the mammal lineage some 55 million years ago, and cetaceans and primates have not shared an ancestor for 95 million years. Therefore, primates and cetaceans have existed on two very different evolutionary trajectories for an extended period of time, resulting in both different bodies and different brains.
It is estimated that 34 million years ago, dolphins existed as big creatures with teeth akin to those of a wolf. Scientists suggest that around this time, the dolphin’s ancestors experienced a period of significant oceanic cooling, that altered food stores and the environment in which the creatures lived. As a result, dolphins altered their hunting customs. Their imposing teeth became smaller, the size of a dolphin’s teeth today, and their brains grew in size. Dolphins began to hunt schools of smaller fish collectively, rather than individuals hunting large fish alone. It is understood that with oceanic cooling, came the beginnings of echo location, notably in changes to the inner ear bones in dolphins at the time. As such, dolphins became more communicative and social, with the means and the need to speak with one another, and probably more intelligent as a result.
It is likely that before we overtook them, dolphins were the most intelligent creatures on the planet (more so, even, than chimpanzees), as relative to body size, a dolphin’s brain is one of the largest among the animal kingdom. Some scientists theorise that dolphins have larger brains to process the information from their echolocation system, although this cannot be proven. Nevertheless, it is still widely acknowledged that a large brain is more likely to evolve in order to support more complex cognitive abilities.
A dolphin’s extremely complicated neocortex - the segment of the brain responsible for problem solving - is accountable for a human-like intelligence. Individual whistles produced by dolphins demonstrate a self-awareness, (the knowledge that one exists as an individual being), that is present in the brain’s pre-frontal cortex. Besides dolphins, this awareness appears to only exist in humans and large brained primates. Furthermore, a dolphin’s well developed paralimbic system is essential to processing emotions, a trait that is integral in the forging of social and emotional connections between dolphins. Von Economo neurons (known as Gangly neutrons) have been discovered within dolphins’ brains; these are present in humans and apes, two of the most intelligent creatures on the planet, and have been linked to social cognition, emotional intelligence, and even theory of mind—the ability to perceive what others are thinking. To add to this, the degree to which the cerebral cortex is folded is known to be a measure of intelligence. The more folded the cortex, the more room within the brain to house additional neurons (brain cells) with which to perform processing of information. It is widely accepted that the only animal to have a more folded cortex than man is the dolphin, acting as an indication to just how smart the creatures are.
As of yet, scientists have not discovered a method through which to accurately quantify intelligence in animals. Thus, we must rely on the composition of the dolphin’s brain, and the many astounding feats dolphins continue to perform daily, as evidence of their innate intelligence. Although it is unlikely that dolphins will take over the world at any point in the near future, there is a lot to be learned from these loquacious creatures—the decoding of dolphin vocalisation, particularly, being one of the greatest enigmas of the present. However, the question persists, will our efforts be in vain if the very species we would attempt to study, is rendered extinct?
By Schuyler Daffey