My Science School

In 1796, an English doctor called Edward Jenner (1749-1823) gave the first vaccination. He realized that milkmaids who caught cowpox did not catch the very dangerous disease of smallpox. By injecting the cowpox virus into a child, he was able to vaccinate him against the more serious disease. As the body fights the virus, antibodies are formed in the blood that prevents further infections or infection by some similar viruses. Today, huge vaccination programmers ensure that most children are protected against a range of diseases.

A person may become immune to a specific disease in several ways. For some illnesses, such as measles and chickenpox, having the disease usually leads to lifelong immunity to it. Vaccination is another way to become immune to a disease. Both ways of gaining immunity, either from having an illness or from vaccination, are examples of active immunity. Active immunity results when a person’s immune system works to produce antibodies and activate other immune cells to certain pathogens. If the person encounters that pathogen again, long-lasting immune cells specific to it will already be primed to fight it.

A different type of immunity, called passive immunity, results when a person is given someone else’s antibodies. When these antibodies are introduced into the person’s body, the “loaned” antibodies help prevent or fight certain infectious diseases. The protection offered by passive immunization is short-lived, usually lasting only a few weeks or months. But it helps protect right away.

Infants benefit from passive immunity acquired when their mothers’ antibodies and pathogen-fighting white cells cross the placenta to reach the developing children, especially in the third trimester. A substance called colostrum, which an infant receives during nursing sessions in the first days after birth and before the mother begins producing “true” breast milk, is rich in antibodies and provides protection for the infant. Breast milk, though not as rich in protective components as colostrum, also contains antibodies that pass to the nursing infant. This protection provided by the mother, however, is short-lived. During the first few months of life, maternal antibody levels in the infant fall, and protection fades by about six months of age.

Passive immunity can be induced artificially when antibodies are given as a medication to a nonimmune individual. These antibodies may come from the pooled and purified blood products of immune people or from non-human immune animals, such as horses. In fact, the earliest antibody-containing preparations used against infectious diseases came from horses, sheep, and rabbits.

Research chemists examine different chemicals to find out how they react with other chemicals and with living cells. When a mixture of chemicals is thought to have potential in the treatment of certain conditions, various combinations of the chemicals will be tested to see whether they might be dangerous to living things. Tests on individual cells and on animals are made before human beings are given the new drug. Many people think that drug-testing on animals is wrong, but others feel that this is the best way to make sure that drugs are safe. Trials of the drug, in which some patients are given a placebo (a drug with no active ingredients), carried out to assess the drug’s effectiveness. It is usually only after many years of testing and monitoring that the drug is released for use by doctors.

The journey will have begun in a university laboratory where researchers, with grants from the research bodies or the pharmaceutical industry, have undertaken basic research to understand the processes behind a disease, often at a cellular or molecular level. It is through better understanding of disease processes and pathways that targets for new treatments are identified. This might be a gene or protein instrumental to the disease process that a new treatment could interfere with, for example, by blocking an essential receptor.

Once a potential target has been identified, researchers will then search for a molecule or compound that acts on this target. Historically, researchers have looked to natural compounds from plants, fungi or marine animals to provide the basis for these candidate drugs but, increasingly, scientists are using knowledge gained from the study of genetics and proteins to create new molecules using computers. As many as 10,000 compounds may be considered and whittled down to just 10 to 20 that could theoretically interfere with the disease process.

The next stage is to confirm that these molecules have an effect and that they are safe. Before any molecules are given to humans, safety and efficacy tests are conducted using computerised models, cells and animals. Around half of candidates make it through this pre-clinical testing stage and these five to 10 remaining compounds are now ready to be tested in humans for the first time. In the UK, approval by the Medicines and Healthcare products Regulatory Agency (MHRA) is required before any testing in humans can occur. The company will put in a clinical trial application (CTA), which will be reviewed by medical and scientific experts, who will decide whether or not sufficient preliminary research has been conducted to allow testing in humans to go ahead.

Each year sees a couple of dozen new drugs licensed for use, but in their wake there will be tens of thousands of candidate drugs that fell by the wayside. The research and development journey of those new drugs that make it to market will have taken around 12 years and cost around £1.15bn.

Understanding the cause of an illness can often help a doctor to bring a patient back to good health or to suggest ways to prevent the illness from recurring or affecting other people. Illness may he caused by an accident, which physically affects part of the body, or it may be brought about by tiny organisms such as bacteria and viruses. Antibiotics are used to treat bacterial infections, while antiviral drugs attack viruses. In both cases, some disease-causing organisms are resistant to drug therapy. Occasionally, the cells of the body seem to act in destructive ways for no obvious reason. This is what happens in some forms of cancer. However, researchers are finding new ways to combat disease all the time.

A complex illness contains two or more elements of illness, causal illness, injury illness and blockage illness, with a single cause. A complex illness requires a cure for each illness element.

For complex illnesses, the first cure is to address the cause.  The second cure is to heal the damage, the third to transform the negative attributes that resulted from illness and from healing. It is possible, sometimes necessary to work on elemental cures out of sequence, or at the same time. However, cures can seldom be completed out of sequence, because the prior illness is a cause, and the illness will recur.

The hierarchy is also a hierarchy of life and of health. It is also useful to view the hierarchy of illness. An illness can exist in a single cell, the simplest life form. A single cell might have an illness with a single cause that causes an injury that is healed, but leaves a blockage resulting in congestion.

An illness might exist in a bodily tissue, independent of the cells comprising the tissue.  A tissue is a layer of life above individual cells.  A tissue might have an illness because that is not a cause of cellular illnesses that leads to tissue injury, which heals and leaves a tissue blockage, resulting in congestion in the tissue.  In the same manner, a limb, or an organ, or an organ system might have a simple or compound illness.

An illness can be based in an organ, an organ system, or in the body.  This is the common view of much of today’s medical practice. It is sometimes a useful view, sometimes not so useful. The illness of the body, like that of a cell, or that of a tissue might begin with a cause, or as an injury or a blockage, caused by an internal or external factor.

An illness might also arise in the mind, or the spirit, or even the community aspects of a life entity, from internal or external causes. An illness might result in damage to the mind, or to the spirit, or to the community aspects of the patient, which when healing is not perfect, results in a negative attribute – leading to congestion, and possibly even a new illness.

Anaesthesia prevents pain signals from being received by the brain, so that the pain is not felt by the patient. Hundreds of years ago there were few ways to relieve a patient’s pain during surgery. Alcohol might be used, but it was not very effective. It was not until the nineteenth century that anaesthetic drugs began to be widely used. The first operation to be performed using a general anaesthetic was by an American surgeon, in 1842.

Anaesthesia refers to the practice of blocking the feeling of pain to allow medical and surgical procedures to be undertaken without pain.

 An ancient Italian practice was to cover a patient’s head with a wooden bowl and beat on it repeatedly until the patient lost consciousness. Presumably this method resulted in a number of side-effects the patient would not have found beneficial.

Opium and alcohol were regularly used to produce insensibility, both of which also had a number of negative side effects and neither could dull the pain completely. Few operations were possible and speed was the determinant of a successful surgeon. Patients were often tied or held down and the abdomen, chest and skull were effectively inoperable. Surgery was a last, and extremely painful, resort.

On October 16, 1846, an American dentist, William Morton, proved to the world that ether causes complete insensibility to pain during an operation performed in front of a crowd of doctors and students at the Massachusetts General Hospital. Morton instructed the patient to inhale the ether vapour and, once the patient was suitably sedated, a tumour was removed from his neck. The patient felt no pain. This demonstration transformed medical practice.

Archaeologists have found skulls, dating from at least 10,000 years ago, that have holes drilled into them. Because bone has begun to grow around the holes, they were clearly made while the person was still alive. It is believed that this technique, called trepanning, was the first operation. It was probably done to relieve headaches or to let out evil spirits that were thought to be trapped inside the patient’s head.

The history of dental and surgical procedures reaches back to the Neolithic and pre-Classical ages. The first evidence of a surgical procedure is that of trephining, or cutting a small hole in the head. This procedure was practiced as early as 3000 BC and continued through the middle Ages and even into the Renaissance.  The initial purpose of trephining in ancient cultures is unknown; although some hypothesize it may have been used to rid the body of spirits. The practice was widespread throughout Europe, Africa, and South America. Evidence of healed skulls suggests some patients survived the procedure. Trephining continued in Ancient Egypt as a method of treating migraines. In South America, ancient Mayans practiced dental surgery by filling cavities with precious stones including jadeite, turquoise, quartz, and hematite, among others. It is supposed that these procedures were for ritual or religious purposes, rather than health or cosmetic reasons.

Ancient Greeks also performed some surgical procedures including setting broken bones, bloodletting, draining lungs of patients with pneumonia, and amputations. The Greeks had new, iron tools at their disposal, yet the risk of infection or death was still high. Hippocrates’ theory of four humors influenced medicine for hundreds of years. He claimed that the humors (black bile, yellow bile, phlegm, and blood which coincided with the elements earth, fire, water, and air, respectively) exist in the body, and bloodletting (or the draining of blood), among other procedures, balanced them. Ancient Roman physician Galen was heavily influenced by the Greeks. He served for three years as doctor to Roman gladiators and as the Emperor’s surgeon, gaining hands-on surgical experience. Romans continued with trephining, amputations, and eye surgery. Beginning in 900 AD, Al-Zahrawi, a famous Islamic surgeon, wrote books focused on orthopedics, military surgery, and ear, nose, and throat surgery, further influencing Islamic and Western medical practitioners.

Hippocrates is often described as “the father of modern medicine”. He was a Greek doctor, living in the fourth and fifth centuries BC , who taught that a doctor’s first duty is to his or her patient and that the aim must at all times be to try to do good rather than harm. When they qualify, many modern doctors take the Hippocratic Oath, promising to follow these principles throughout their careers.

Hippocrates was born around 460 BC on the island of Kos, Greece. He became known as the founder of medicine and was regarded as the greatest physician of his time.

He based his medical practice on observations and on the study of the human body. He held the belief that illness had a physical and a rational explanation. He rejected the views of his time that considered illness to be caused by superstitions and by possession of evil spirits and disfavor of the gods.

Hippocrates teaching Hippocrates held the belief that the body must be treated as a whole and not just a series of parts. He accurately described disease symptoms and was the first physician to accurately describe the symptoms of pneumonia, as well as epilepsy in children. He believed in the natural healing process of rest, a good diet, fresh air and cleanliness. He noted that there were individual differences in the severity of disease symptoms and that some individuals were better able to cope with their disease and illness than others. He was also the first physician that held the belief that thoughts, ideas, and feelings come from the brain and not the heart as others of his time believed.

Hippocrates traveled throughout Greece practicing his medicine. He founded a medical school on the island of Kos, Greece and began teaching his ideas. He soon developed an Oath of Medical Ethics for physicians to follow. This Oath is taken by physicians today as they begin their medical practice. He died in 377 BC. Today Hippocrates is known as the “Father of Medicine”.