Posted in Psychology & Medicine

The Man With The Golden Arm

In 1954, an 18-year-old Australian man by the name of James Harrison began donating blood. This is certainly not an unusual fact – over 100 million units of blood are donated worldwide each year. Harrison required massive amounts of blood transfusion during a major chest surgery he required 4 years prior. Knowing that he owed his life to the generous gift of blood from others, he pledged to donate blood as soon as he met the required age for it.

Soon after the first few donations, it was discovered that his blood had a peculiar property. Harrison’s blood contained unusually strong, long-lasting antibodies against a protein called the D Rh group antigen, or Rh(D).

Why was this such an important discovery?

In blood transfusion, blood types are crucial as transfusing the wrong type of blood can trigger an immune reaction in the donor’s body, potentially killing them. This is because red blood cells (that carry oxygen in the blood) are coated with different proteins called antigens. Your body ignores antigens that it is used to, but if it detects any new protein, it will create antibodies and viciously attack the cell as it thinks it is an infection.

Most people know their blood type as A, B, AB or O. A and B are the two most prominent antigens for red cells. If you are type A, you have A antigens. Type B have B antigens. Type AB have both antigens, while type O have neither antigens.

So, for example, if you transfuse type AB blood into a type B person, the donor’s immune system ignores the B antigen, but since it has never seen A antigens, it attacks the new blood and can make the donor very sick (or die).

The second most prominent antigen is Rh(D) (previously Rhesus factor). If you have it, you get a “+” next to the ABO typing (e.g. B+); if you don’t, you get a “” (e.g. O-, the “universal donor” blood).

Rh(D) was a huge issue in medicine because it resulted in many babies dying or suffering brain damage due to haemolytic disease of the newborn (HDN) – a transfusion reaction where the mother’s immune system attacks the fetus due to different blood typing.

The so-called “anti-D” antibodies that were discovered in Harrison’s blood provided scientists with a weapon to fight against HDN.

HDN happens when a Rh negative woman develops antibodies to Rh(D), then has a baby with Rh positive blood. For example, if a Rh- woman has a Rh+ baby in the first pregnancy, the body detects the baby’s blood during birth, senses the Rh(D), then develops antibodies so it can fight it next time.

If you give the woman anti-D before the body has a chance to detect the antigen, the anti-D will immediately attach to all the Rh(D) antigens, shielding it from the body. Therefore, the woman never becomes sensitised to the antigen and doesn’t make antibodies. No antibodies, no HDN.

James Harrison was well aware of the power of his blood, so he proceeded to donate blood every two weeks for 57 years – over a 1000 donations. It is estimated that his blood helped save the lives of 2.4 million babies worldwide, including his own grandchild. Hence, he is known as The Man With The Golden Arm.

+1
Posted in Science & Nature

Virgin Birth

Although the concept of virgin birth (i.e. conception without intercourse) is common in many religions, there is no conclusive evidence of actual human virgin birth in recorded history. Except in one medical article written in 1874 by a Dr Capers.

In this article, Dr Capers describes a case study of a miraculous conception during the Battle of Raymond during the US Civil War. A soldier was shot in the testicles and the musket ball carried the non-musket ball (read: testicle) into the uterus of a girl working in a nearby field. The doctor attended to the girl who was shot and treated the wound in her abdomen. The bullet was not found.

Over the following nine months, the doctor realised the girl was pregnant, although she claimed to be a virgin. After nine months, a healthy boy was born. Stranger yet, the doctor realised the boy’s scrotum was unusually swollen and upon examination, found that he was carrying the musket ball that impregnated the girl in the first place. He thus concluded that the testicle that was carried by the musket ball was lodged inside her uterus and sperm leaked out. The soldier was eventually found and was told about this bizarre story and the two were married.

This case study has become a famous story told by doctors around the world. Unfortunately, it is completely false and the doctor who wrote the article admitted to faking it to amuse himself. Ergo, there are still no recorded cases of a virgin birth in humans.

The closest to a virgin birth that was recorded is a case study of a young woman who was performing oral sex on a man. She was found by her boyfriend during the act and the boyfriend stabbed her and her lover with a knife. The knife injured her oesophagus, causing the sperm in it to track down the abdomen and down to her reproductive organs. By a stroke of luck, an egg was misplaced during ovulation, causing it to drift into the abdomen instead of the fallopian tube (ectopic pregnancy), and met with the sperm. The egg was then fertilised and the girl presented to the hospital three months later with excruciating abdominal pain. The ectopic fetus was removed.

0
Posted in Science & Nature

Caesarean Section

(To read about how babies are made and born, read the From Cell to Birth miniseries! https://jineralknowledge.com/tag/arkrepro/?order=asc)

Most animals give birth through a female’s vagina. Of course humans are the same when it comes to natural birth, but nowadays, it is not uncommon to find women wanting a caesarean instead of the traditional method. A caesarean (also called C-section) is a surgical procedure where the fetus is taken out by cutting through the lower abdomen into the uterus. The history of caesareans is quite dark. Back in the old days when medicine was not advanced, caesareans were mostly used to rescue fetuses from mothers who had died during childbirth. The first record of a successful caesarean where the mother survived dates back to the 1500s. Many people believe the word “caesarean” came from the Roman emperor Julius Caesar, who was allegedly born via a caesarean. However, it was rare for caesareans to be performed in Roman times and even if they were, the mothers almost certainly died in the process. Given that his mother was alive and healthy well into his adulthood, it is highly unlikely that Caesar was born by caesarean (there are no concrete records of it either).

There is much debate to whether a caesarean is better or worse than natural birth (except in emergency situations where a caesarean is required). According to research (in cases without known risks to the fetus), the mortality rate is definitely higher in babies born by caesarean compared to those born naturally. This is most likely due to a caesarean bypassing some of the physiological changes that occur during vaginal birth.

Another debate is about the use of general versus regional anaesthesia (spinal block) when doing a caesarean. A fascinating fact about childbirth is that when a baby is born, it cries to expand its lungs but then quietens down for about an hour (unless it is in pain or there is some stimuli). This is possibly a mechanism to allow bonding between the mother and baby. New mothers often remember the moments following the birth of the child as extremely emotional and blissful. Contrastingly, mothers who are under general anaesthesia and not awake when their child is born bond less with the baby initially (some mothers do not even recognise the baby as their own). Thus, unless it is an emergency caesarean, a spinal block (which allows the mother to be awake and painless) is preferable over general anaesthesia.

Lastly, it is common tradition to cut the umbilical cord straight after the child is born. But is this okay? When the fetus is in the uterus, it shares its cardiovascular system with the placenta. The umbilical cord connects the two and carries blood to and fro. At any given point, the placenta contains 30~50% of the fetal blood. If the umbilical cord is suddenly cut, the fetus essentially loses this blood, being born in a state of low blood volume. If you look at the umbilical cord, you can see that it is about 1m in length, which is enough for the baby to be put next to the mother’s breasts for breastfeeding and bonding. Perhaps we are cutting the cord too soon, not letting the blood flow back from the placenta to the fetus.

If you think about it, humanity has been giving birth without too many problems to survive generation after generation for 200,000 years (otherwise we would not exist). Although the mortality rate was high, Mother Nature has optimised childbirth over time through evolution. Ergo, it is possible that modern medicine is intervening too much in a natural process. We must always consider whether medical advances are helpful or harmful to us.

image

0
Posted in Psychology & Medicine

Tetanus

Tetanus is an infectious disease caused by a soil-borne bacteria called Clostridium tetani. Patients are often infected soil entering the blood through deep wounds, such as a cut. The bacteria produces a toxin called tetanospasmin which leads to the characteristic symptoms of tetanus involving muscle.

The term tetanus actually refers to a state where skeletal muscle remains contracted and cannot relax due to maximum signalling from the nervous system. Tetanus is associated with some distinct symptoms involving tetanised muscles.

Tetanus starts in the face in the form of lockjaw (jaw clamps shut and cannot be opened) and sardonic risus sardonicus. Risus sardonicus, also known as sardonic grin, is a contorted, malicious-looking smile that is caused by spasms of muscles in the face. A good portrayal of the grin is seen in the Joker’s face from the Batman comic book series.
The disease then progresses to cause stiff neck, spasming of chest and leg muscles and difficulty swallowing. 

A dramatic symptom is opisthotonos, where the patient experiences extremely painful contractions of back muscles causing them to arch their back against their will. Along with lockjaw and risus sardonicus, it is a characteristic sign of tetanus and has been known for centuries. Before it was attributed to tetanus, people used to think the person was possessed by a demon due to the agonised screams and involuntary spasming of the body.

The disease is especially devastating in infants and can be spread to the fetus within the womb. This is because babies do not have a developed passive immune system that can combat the infection. Neonatal tetanus carries a mortality rate of over 90% and is responsible for 15% of all neonatal deaths.

Tetanus is a preventable disease through immunisation. Immunisation is done by injecting an inactive form of the toxin (i.e. cannot cause disease), inducing a reaction by the immune system. This essentially “teaches” the immune system to defend the body against tetanus. By completing a course of three doses and receiving occasional booster shots throughout life, tetanus can be prevented. Pregnant women must be immunised against tetanus to prevent neonatal tetanus (the babies receive scheduled immunisations soon after birth too).

This is one example of how immunisation can effectively prevent fatal diseases in a population.

+1
Posted in Psychology & Medicine

Toxoplasmosis

There is a protozoan parasite called Toxoplasma gondii. This parasite infects many animals through an interesting route. 
The first victim is a mouse. An infected mouse loses its fear of cats, leading it to play fearlessly in front of one until it gets caught and eaten (was Jerry a mouse with toxoplasmosis?). It is unclear how it controls a more advanced animal’s brain, but thanks to this effect, Toxoplasma gondii can infect its intermediate host – a cat.
An infected cat starts excreting parasite eggs with its faeces. If a person forgets to wash their hands or eats food contaminated with cat faeces, they can be infected and become the final host for the parasite.

Usually, Toxoplasma gondii cannot overcome the healthy immune system, but it can infect those with a weaker immune system such as the elderly or pregnant women. Furthermore, it is part of the TORCH complex (toxoplasmosis, rubella, cytomegalovirus, herpes) – a group of infections that commonly cross over from the mother to the fetus in utero. Symptoms are normally flu-like, but if more severe it can cause dysfunction of the eyes, brain and other vital organs. Sometimes it lies dormant until the person’s immune system is weakened, whence it becomes active. Toxoplasmosis is also a possible cause of a miscarriage or infertility.

One fascinating symptom of toxoplasmosis is psychiatric disorders. Because Toxoplasma gondii can infiltrate the brain, it is known to cause depression or even schizophrenia. As cats are the most common intermediate host, cat owners are more susceptible to toxoplasmosis. Because of this, there is a theory that “crazy old cat ladies” are in fact toxoplasmosis patients.

0
Posted in Science & Nature

From Cell To Birth: Growth

After implantation, the embryo quickly grows from a ball of cells into what will be a fully-formed baby. However, it first needs a way to feed: the placenta.
It is an organ that actively takes nutrients and oxygen from the mother’s blood, exchanging it for the embryo’s waste products. It is extremely effective in keeping the fetus alive and protects it from infections or the mother’s immune system.
The blood is carried by the umbilical cord, which plugs into the belly button. This cord is the lifeline throughout term, and disrupting the blood supply will lead to permanent brain damage or even death.

In the first 10 weeks, the blastocyst develops into a very primitive disk-like object that shares no resemblance to a person. It keeps growing and differentiating at a rapid rate (almost doubling in size per week) until it forms an embryo that is more familiar, roughly about week 6. Interestingly, a human embryo looks almost identical to embryos of rabbits, chickens, turtles and fish, showing how all animals shared a common ancestor in the course of evolution. At this stage, the embryo has features such as gills, a tail and a fish-like appearance.

After 10 weeks, the embryo has grown to about 5~8cm (almost 10~20 times the size at week 6), and is now called a fetus. It begins to properly grow organs, and resembles a miniature baby with primitive features.
It continues to grow for the next 30 weeks, continuously relying on the mother for nutrition and life support.

Many different factors contribute to premature birth and IUGR (intrauterine growth restriction), which leads to the birth of a small baby. This may result in less developed organs (especially the lungs) and may affect the health of the newborn throughout its life. There are also many poisons known to harm the development of the embryo/fetus, such as alcohol, nicotine, cocaine, heroin and much more. These should be avoided from a few weeks before conception onwards (even after birth while breastfeeding).

By about 38 weeks, the lungs (the last organs to fully mature) are ready and the fetus is upside down. It is ready to leave the womb, and thus sends a signal to the mother, known as labour. This is when the arduous process of childbirth begins.

(Full series here: https://jineralknowledge.com/tag/arkrepro/?order=asc)

0
Posted in Science & Nature

From Cell To Birth: Implantation

When an egg is fertilised by the sperm, it is called a zygote. This zygote immediately starts to divide at an exponential rate, to achieve the feat of transforming from a single cell to a 3kg baby. The division and growth happens as the zygote slowly drifts towards the uterus, where it can secure itself.

30 hours after fertilisation, the zygote is now 2 cells.
72 hours, the zygote is now 16 cells.
96 hours, the zygote is now a ball of over 60 cells, and now called a morula.
108 hours, the morula has a cavity inside, and is called a blastocyst.
The blastocyst, essentially a shell of cells with a mass of cells at one point, hatches out of the zona pellucida as it is now much bigger.
To gain the massive amount of energy required for development, the zygote eats up simple sugars in the fallopian tube during its travel.

image

As mentioned before, when pregnancy does not happen, the endometrium is shed and flushed out. To prevent this, the blastocyst secretes something called βhCG, keeping the corpus luteum alive, which secretes progesterone to maintain the endometrium. As the endometrium is the fertile “soil” where the embryo will grow, this is a vital step (βhCG is the hormone tested in a pregnancy test).
When the blastocyst reaches the uterus, it finds a safe spot on the endometrium, with the inner cell mass facing the wall. This is where implantation begins.

After clinging tightly to the endometrial cells, the blastocyst fuses some of its cells into a digging tool that can eat away at the endometrium. As it digests away the cells, the blastocyst slowly burrows in until it is completely embedded inside. Cells invade the hollowed space, firmly securing the blastocyst while destroying blood vessels and glands to release nutrients, securing a supply line. Now, it can start its rapid development into an embryo as it leeches away the mother’s nutrients.

A foreign body latching on to the host’s cells, digesting away tissue and leeching blood and nutrients – an embryo acts exactly like a parasite, to ensure that it can safely survive the 40-week gestation. In fact, an embryo can implant itself almost anywhere in the body, such as the fallopian tubes, ovaries or even the gut, as long as there is a secure blood supply. This is called an ectopic pregnancy, and can be an extremely dangerous scenario to both the mother and developing fetus.

(Full series here: https://jineralknowledge.com/tag/arkrepro/?order=asc)

0