Category Medical World

THE CURIOUS CASE OF EMM NEGATIVE

India has reported its first case of EMM negative blood. What is unique about the type? Why does it not find a place in the existing blood groups?

IN SCHOOL DESK

One of the first things that schools ask when students enroll is their blood group. This crucial information is added to the identity card and student files so that, in case of a medical emergency, the information is available at hand. But can you imagine a scenario when a lab is unable to identify your blood group because it is extremely rare? That’s what happened when a 65-year-old man in Gujarat who had gone for cardiac treatment, tried to find out his blood group.

Even specialists were left puzzled as his blood sample did not seem to match others. The patient needed to know his blood group in order to have a compatible donor who could give him blood for a heart surgery. Only after a long ordeal ending with his blood sample being sent to the United States for testing, did the man find out that he had EMM negative blood. He is the first recorded case in India to have such a blood type and the tenth in the world. The blood group has been assigned with the symbol ISBT042.

What are blood types?

Blood is characterised into types to prevent adverse reactions during blood transfusions. In general, we know of the blood types A, B, O or AB. Further, these groups take on a negative or positive factor.

However, there are 42 different types of blood systems, including A, B, O, Rh, and Duffy. The names come from the ABO antigens, which are basically protein molecules that are found on our red blood cells. In most blood groups, EMM is present. But there are rare cases where EMM is negative.

In the case of the Gujarat man, even his children’s blood samples were not a perfect match and he could have had a reaction if their blood was given to him.

Why is the ISBT042 blood type so rare?

Understanding the Emm antigen has been a struggle even for scientists. But by studying those with the blood type and comparing their samples with those of relatives, scientists have found that a deletion in a gene could be responsible for the blood type. People with EMM negative blood group can’t donate blood to anyone or accept blood from anyone.

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What is ASMR (AUTONOMOUS SENSORY MERIDIAN RESPONSE)?

It refers to the tingling sensation one experiences due to various kinds of feel-good sounds.

Autonomous sensory meridian response (ASMR) is a term that describes a spontaneous, enjoyable, and relaxing tingling sensation that begins in the scalp and radiates down the spine to your upper back shoulders, and legs. The sensation is triggered by various stimuli such as gentle whispering, brushing hair, soft finger tapping, crumpling or folding of paper, etc. The term was coined by Jennifer Allen in 2010 when she formed a Facebook group dedicated to ASMR. It is colloquially known as ‘brain massage, head tingle, brain tingle’, or ‘spine tingle. ASMR is being currently studied by scientists and psychologists.

According to an ongoing online survey, ASMR is experienced by people of all ages across the globe irrespective of race or culture, suggesting it is a sa biological response. So far scientists can’t explain why it works for many people or why it doesn’t affect some people. ASMR has, of late, become a YouTube phenomenon with millions of ASMR videos flooding the Internet. They feature someone talking softly, making soothing sounds, gently scratching various surfaces with fingernails, etc. People watch these videos to induce sleep or relaxation. However, professionals caution against depending much on ASMR, as its drawbacks, if any are yet to be fully ascertained.

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WHAT IS RED LIST INDEX?

Put together by the International Union for the Conservation of Nature (IUCN), the IUCN Red List tells us how likely it is for a species to go extinct (such as EN – endangered, VU vulnerable, etc.). But the list does not offer insights into meaningful trends in the status of biodiversity. To address this, the Red List Index (RLI) has been created to show trends in the status of groups of species based only on genuine improvement or deterioration. Right now, RLI is available for birds, mammals, amphibians, cycads (vascular plants), and corals.

Sampled approach

Producing indices of change in extinction risk by comprehensively assessing whole species groups, while feasible for well studied groups with relatively few species, is not suitable for all taxonomic groups. Assessing every species in the larger and lesser known groups which comprise the majority of the world’s biodiversity, such as fungi, invertebrates (particularly insects) and plants, is not practical.

The Red List Index (sampled approach) (SRLI) has been developed in order to determine the threat status and also trends of lesser-known and less charismatic species groups. It is a collaboration between IUCN members and is coordinated through the Institute of Zoology (IoZ), the research division of the Zoological Society of London (ZSL). The SRLI is based on a representative sample of species selected from taxonomic groups within animals (invertebrates and vertebrates), fungi and plants.

Assessment of the selected species will provide baseline information on the current status of biodiversity. Reassessment at regular intervals will identify changes in threat status over time to provide a more broadly representative picture of biodiversity change.

Applications

The aim is that the SRLI will aid in the production of a global biodiversity indicator capable of measuring whether the rate of biodiversity loss has been reduced. In addition, it will help to develop a better understanding of which taxonomic groups, realms or ecosystems are deteriorating the most rapidly, why species are threatened, where they are threatened, what conservation actions exist and which actions are needed. The aim is to provide policy makers, resource managers, scientists, educators, conservation practitioners and the general public with more thorough knowledge of biodiversity change and further tools with which to make informed decisions.

In April 2002 at the Convention on Biological Diversity (CBD), 188 Nations committed themselves to actions to: “… achieve, by 2010, a significant reduction of the current rate of biodiversity loss at the global, regional and national levels…” The RLI has been adopted by the CBD as one of the indicators to measure progress towards this important target, and specifically to monitor changes in threat status of species.

Credit : Wikipedia

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HOW DOCTORS STARTED USING STETHOSCOPES TO DIAGNOSE PROBLEMS WITH THE CHEST?

The practice of using stethoscopes started in a hospital in Paris, in the early 19th Century.

The Necker-Enfants Malades Hospital in Paris provided specialised medical care. Rene Laennec, one of the doctors there, was trained to use sound to diagnose diseases of the chest.

One day in 1816, a young woman who had a heart problem came to consult Dr. Laennec. Ordinarily, the physician would have put his ear to the woman’s chest and listened to her heartbeats to detect if there was any aberration. But the woman who came to see Dr. Laennec was rather plump. Uncomfortable with the idea of putting his ear to her chest, the doctor’s eyes fell on a newspaper lying there…and he got a brainwave!

He rolled the newspaper into a cylinder and applied one end of it to the region of the woman’s heart and the other to his ear. And then his own heart thumped in joy and excitement! He could hear her heartbeats more clearly than if he had put his ear directly to her chest. It was a landmark moment in medical science.

Laennec fashioned a hollow, wooden cylinder and catalogued the various sounds he could hear through it when applied to a patient’s chest, and what the sounds indicated about the health of the patient. He sent his findings to the Academy of Science, in Paris.

It was not long before his invention began to be used by physicians all over Europe.

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WHAT IS CRYOGENIC ELECTRON MICROSCOPY?

Did you know scientists hope to develop targeted drugs for hard-to-treat diseace using the technique?

Ultra high-definition 3D videos of cells inside the body taken by an advanced microscope are creating a revolution in modern biology. Previously, transmission electron microscope (TEM) images of living cells (called biomolecules) were indistinct blobs. This was because the high-energy electron beams would dry out the water surrounding the molecules and burn them.

In cryogenic electron microscopy (cryo-EM), biomolecules are cooled to extremely low temperatures and embedded in vitrified water (ice that has no crystals). This ensures that they are preserved intact. The three scientists who developed the cryo-EM technique won the 2017 Nobel Prize in Chemistry.

The current level of sophistication in the cryo-EM technique is largely due to advances in camera technology, image processing and computer software. The biomolecules are photographed from thousands of different angles and at different stages. The images are put together to create a video, allowing researchers to see the structure of the molecules in live action within the cell.

Using this technique, scientists hope to develop targeted drugs for hard-to-treat diseases such as dementia and Parkinson’s.

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WHAT TYPE OF VACCINE IS R21?

Scientists behind the Oxford-AstraZeneca coronavirus shot have produced the vaccine. “This was by far a much more difficult vaccine to make work.” Adrian Hill, the Jenner Institute’s director, said in northern Tanzania on a visit to field trials of the R21/Matrix-M malaria vaccine.

While the coronavirus responsible for Covid-19 has 12 genes, Plasmodium-the parasite that causes malaria – has more than 5,000 genes. It’s an organism that infects the liver and bloodstream, infecting red blood cells.  Hill explains that R21/Matrix-M combines the R21 vaccine with a vaccine booster or adjuvant Matrix-M, which stimulates the human immune system to attack the parasite.  When an infectious mosquito feeds on a human being, it injects parasites in a form called sporozoites into the bloodstream, where they travel directly to the liver. The sporozoites divide rapidly, producing around 20,000 merozoites that rupture the liver cells and invade red blood cells.  R21 targets a circumsporozoite protein (CSP) present on the parasite’s surface during the sporozoite stage. CSP rarely mutates among the four strains of malaria parasites that infect humans. The human body does not readily react with a complete immune response to foreign proteins. The R21 focus on CSP boosted by the proprietary Novavax adjuvant- produces a more robust, better-targeted antibody response.  Clinical trials are now moving to the third phase in four countries across Africa – Mali, Tanzania, Kenya, and Burkina Faso.

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