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Subject: Biotech and Medical Sciences

  • Xeno-Transplantation and Related Issues

    Recently, the University Of Maryland School Of Medicine announced that it had successfully transplanted a genetically-modified pig heart into a patient with severe ailments.

    What is Xenotransplantation?

    • Xenotransplantation, or transplanting organs across different species, was first tried in humans in the 1980s.
    • The experiment was abandoned after the famous case of the American Baby Fae who was born with a congenital heart defect and received a baboon heart in 1984.
    • However, pig heart valves have been used for replacing damaged valves in humans for over 50 years now.
    • Nowadays, harvesting organs from genetically engineered pigs is seen as a viable alternative to meet organs shortage.

    How the pigs are genetically engineered?

    • The donor pig underwent 10 genetic modifications, by which the genes responsible for the rapid rejection of foreign organs by the human body were inactivated or knocked out.
    • Four pig genes were removed, and six human genes were added.
    • “GalSafe” pigs, or pigs that had undergone editing to knock out a gene that codes for Alpha-gal (a sugar molecule) were used.
    • Alpha-gal can elicit a devastating immune response in humans.
    • GalSafe pigs have been well studied, and are approved by the US Food and Drug Administration (FDA) for use in pharmacology.

    Why pursue xenotransplantation?

    • Modern scientific supporters of xenotransplantation argue that the potential benefits to society outweigh the risks, making pursuing xenotransplantation the moral choice.
    • None of the major religions object to the use of genetically modified pig organs for life-saving transplantation.

    A crucial case in India

    • Harvesting organs from genetically engineered pigs is seen as a viable alternative to meet organs shortage.
    • According to the health ministry, around 0.18 million people in India are estimated to suffer from renal failure every year, but only about 6,000 renal transplants are carried out in the country.
    • About 25,000-30,000 liver transplants are needed annually in India but only about 1,500 are being performed.
    • In the case of the heart, 50,000 people suffer from heart failure and are in need of a heart transplant.
    • Yet, only 10-15 heart transplants are carried out in India each year.

    Issues with Xenotransplantation

    Besides scientific challenges, there are several ethical challenges to overcome:

    • Animal rights: Many, including animal rights groups, strongly oppose killing animals to harvest their organs for human use.
    • Decreased life expectancy: In the 1960s, many organs came from the chimpanzees, and were transferred into people that were deathly ill, and in turn, did not live much longer afterwards.
    • Religious violations: Certain animals such as pork are strictly forbidden in Islam and many other religions.
    • Informed consent: Autonomy and informed consent are important when considering the future uses of xenotransplantation.
    • Threats of zoonosis: The safety of public health is a factor to be considered. We are already battling the biggest zoonotic disease threat.

     

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  • Traditional vaccines just as effective, say US Scientists

    Vaccines like Biological E’s Corbevax and Bharat Biotech’s Covaxin that are made by traditional methods are “just as effective” as the latest mRNA technology-based vaccines a/c to US scientists.

    What are Vaccines?

    • A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease.
    • It typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins.

    Types of Vaccines

    There are several types of vaccines, including:

    • Inactivated vaccines
    • Live-attenuated vaccines
    • Messenger RNA (mRNA) vaccines
    • Subunit, recombinant, polysaccharide, and conjugate vaccines
    • Viral vector vaccines

    [1] Inactivated vaccines

    • Inactivated vaccines use the killed version of the germ that causes a disease.
    • Inactivated vaccines usually don’t provide immunity (protection) that’s as strong as live vaccines.
    • So you may need several doses over time (booster shots) in order to get ongoing immunity against diseases.
    • Inactivated vaccines are used to protect against: Hepatitis A, Flu (shot only), Polio (shot only), Rabies etc.

    [2] Live-attenuated vaccines

    • Live vaccines use a weakened (or attenuated) form of the germ that causes a disease.
    • Because these vaccines are so similar to natural infection that they help prevent, they create a strong and long-lasting immune response.
    • Just 1 or 2 doses of most live vaccines can give you a lifetime of protection against a germ and the disease it causes.
    • They need to be kept cool in refrigerated conditions.
    • Live vaccines are used to protect against Measles, mumps, rubella (MMR), Rotavirus, Smallpox, Chickenpox, Yellow fever

    [3] Messenger RNA vaccines

    • Researchers have been studying and working with mRNA vaccines for decades and this technology was used to make some of the COVID-19 vaccines.
    • mRNA vaccines make proteins in order to trigger an immune response.
    • mRNA vaccines have several benefits compared to other types of vaccines, including shorter manufacturing times and, because they do not contain a live virus, no risk of causing disease in the person getting vaccinated.

    How does mRNA vaccine work?

    • The mRNA vaccines function differently from traditional vaccines.
    • Traditional vaccines stimulate an antibody response by injecting a human with antigens.
    • mRNA vaccines inject a fragment of the RNA sequence of a virus directly into the cells, which then stimulate an adaptive immune response mRNA fragment is a specific piece of the virus that carries instructions to build the antigen of the virus.
    • An advantage of RNA vaccines is that they stimulate cellular immunity.

     

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  • What are Chaperone Proteins?

     

    Chaperones are a functionally related group of proteins assisting protein folding in the cell under physiological and stress conditions.

    What are Chaperones?

    • DNA is a linear chain of nucleotides, portions of which are faithfully transcribed into linear messenger RNA.
    • The message in this RNA is translated into strings of amino acids – proteins.
    • Proteins need to take a precise three-dimensional shape to become functional entities.
    • This protein folding does not happen all by itself, at least most of the time.
    • A special bunch of proteins called molecular chaperones assist in correctly folding the protein.

    Functions of chaperone proteins

    • In biological systems, Chaperones play crucial roles.
    • Many molecular chaperones belong to the class of “heat shock” proteins (or stress-response proteins).
    • This is because whenever an organism is subjected to elevated temperatures – a heat shock – proteins in the system begin to lose their native shapes, and chaperones are produced in large quantities to restore order.

    General need of chaperones

    Chaperones are needed under physiological conditions too, for normal cellular function since misfolding of proteins can cause a number of diseases.

    • Alpha-synuclein protein, present in neurons, is wrongly folded in Parkinson’s disease.
    • Brains of Alzheimer’s patients have plaques formed from aggregates of amyloid beta-peptide.
    • This accumulation of amyloid fibrils is toxic, leading to widespread destruction of neurons – a ‘neurodegenerative’ disorder.
    • Aberrant folding of crystallins of the eye lens leads to cataracts.

    Types of Chaperones

    • Major chaperones in humans include HSP70, HSC70 and HSP90: the numbers express the size of the proteins in kilodaltons.
    • In normal cells 1%–2% of all proteins present are heat shock proteins.
    • This number rises threefold during stressful conditions.

    HSC70: The molecular thermometer

    • HSC70 appears to be more like a molecular thermometer, with an ability to sense cold temperatures.
    • It is induced by heat, whereas HSC70 is always present at high levels in normal cells.
    • This knowledge comes from the study of an intriguing set of disorders, exemplified by Familial Cold Autoinflammatory Syndrome (FCAS).

    HSC70 and HSP90: Role in Cancer

    • Cancer cells divide at a break-neck pace, and heat shock proteins are very important in maintaining the stressful cancerous state.
    • An overabundance of heat shock proteins in cancer cells is an indicator of a poor prognosis. Cancerous cells accumulate mutations in proteins that would normally suppress tumours.
    • HSP70 and HSP90 play the roles of villains, as they continue to fold the mutated proteins, thus allowing tumor progression.

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  • What is Omicron Variant?

    A new lineage of SARS-CoV-2 has been designated as a Variant of Concern (VoC) by the World Health Organization (WHO) and has been named Omicron.

    Behind the name: Omicron

    • The WHO has been using Greek letters to refer to the most widely prevalent coronavirus variants, which otherwise carry long scientific names.
    • It had already used 12 letters of the Greek alphabet before the newest variant emerged in South Africa this week.
    • After Mu, the 12th named after a Greek letter, WHO selected the name Omicron, instead of Nu or Xi, the two letters between Mu and Omicron.
    • The WHO said Nu could have been confused with the word ‘new’ while Xi was not picked up following a convention.

    Why is the Omicron variant interesting?

    • The Omicron variant is interesting due to the fact that it has a large number of mutations compared to other prevalent variants circulating across the world.
    • This includes 32 mutations in the spike protein.
    • Many of these mutations lie in the receptor-binding domain of the spike protein, a key part of the protein required for binding to the human receptor proteins for entry into the cell.
    • It can thus play an important role in recognition by antibodies generated due to a previous infection or by vaccines.

    What do spike mutations do?

    • Many of the mutations in the spike protein have been previously suggested to cause resistance to antibodies as well as increased transmission.
    • Thus, there is a possibility that this variant could be more likely to re-infect people who have developed immunity against previous variants of the virus.
    • The behavior of the virus is not yet accurately predictable based on the evidence on individual mutations.

    Does the variant result in vaccine breakthrough infections?

    • Some of the initial individuals identified to be infected with the variant have been vaccinated for COVID-19 and therefore the variant can indeed cause vaccine breakthrough infections.
    • This should not be of concern, since the prevalent variants of concern including Delta have been shown to cause breakthrough infections.
    • Whether the variant causes more breakthrough infections than Delta is not currently known.

    How can we be prepared for the variant?

    • Enhanced surveillance and genome sequencing efforts are essential to detect and track the prevalence of the Omicron variant.
    • Rapid sharing of genome sequences of the virus and the epidemiological data linked with it to publicly available databases will help in developing a better understanding of the variant.
    • Existing public health and social measures need to be strengthened to control and prevent transmission.
    • Enhancing vaccination coverage across different regions along with access to testing, therapeutics and support will be essential for combating the new variant.
    • Equitable access to vaccines would be key to controlling the Omicron variant, and slowing down the emergence of any future variants.

     

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  • Nationwide Pneumococcal Conjugate Vaccine (PCV) drive launched

    Union Health Minister has launched a nationwide expansion of Pneumococcal 13-valent Conjugate Vaccine (PCV) under the Universal Immunisation Programme (UIP).

    Why such drive?

    • Pneumonia was a leading cause of death among children under five, globally and in India.
    • Pneumonia caused by pneumococcus is the most common cause of severe pneumonia in children.
    • Around 16% of deaths in children occur due to pneumonia in India.
    • The nationwide roll-out of PCV will reduce child mortality by around 60%.

    Pneumococcal Conjugate Vaccine (PCV)

    • The PCV is a mix of several bacteria of the pneumococci family, which are known to cause pneumonia—hence ‘conjugate’ is included in the name of the vaccine.
    • PCV prevents pneumococcal disease. It can protect both children and adults from pneumococcal disease.
    • Such conjugate vaccines are made using a combination of two different components.

    Pneumonia vs Pneumococcal pneumonia

    • Pneumonia is a lung disease.
    • Pneumococcal pneumonia, a kind of pneumonia, can infect the upper respiratory tract and can spread to the blood, lungs, middle ear, or nervous system.
    • Pneumococcal disease is a name for any infection caused by bacteria called Streptococcus pneumonia or pneumococcus.
    • Most people carry pneumococcus in their nose and throat, where the bacteria do not cause any symptoms.

    Take this yorker from CSP 2020:

    Q.What is the importance of using Pneumococcal Conjugate Vaccines in India?

    1. These vaccines are effective against pneumonia as well as meningitis and sepsis.
    2. Dependence on antibiotics that are not effective against drug-resistant bacteria can be reduced.
    3. These vaccines have no side effects and cause no allergic reactions.

    Select the correct answer using the code given below:

    (a) 1 only

    (b) 1 and 2 only

    (c) 3 only

    (d) 1, 2 and 3

     

    [wpdiscuz-feedback id=”txjic5odbw” question=”Please leave a feedback on this” opened=”1″]Post your answers here.[/wpdiscuz-feedback]

     

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  • What is Hybrid Immunity?

    A study has shown that a combination of natural infection with a single dose of vaccine provides greater immunity than either natural infection without vaccination or full vaccination in individuals.

    What is the new study?

    • People without prior infection but fully vaccinated with the Pfizer or AstraZeneca vaccine showed a decline in neutralising antibodies over a period of three to seven months.
    • But the decline was much less in vaccinated people with prior infection.
    • People with hybrid immunity had a higher and more durable neutralising antibody response.
    • The hybrid immunity offers stronger protection than just infection or full vaccination alone.

    What is Hybrid Immunity?

    • It is natural immunity from an infection combined with the immunity provided by the vaccine.
    • The immunological advantage from hybrid immunity arises mostly from memory B cells.

    What are memory B cells?

    • In immunology, a memory B cell (MBC) is a type of B lymphocyte that forms part of the adaptive immune system.
    • B lymphocytes are the cells of the immune system that make antibodies to invade pathogens like viruses.
    • They form memory cells that remember the same pathogen for faster antibody production in future infections.

    How do they assist hybrid immunity?

    • While the bulk of antibodies after infection or vaccination decline after a short while, the memory B cells get triggered on subsequent infection or vaccination.
    • The memory B cells triggered by infection and those triggered by vaccination have different responses to viruses.
    • Infection and vaccination expose the spike protein to the immune system in vastly different ways.
    • After full vaccination, antibodies produced by natural infection continued to grow in potency and their breadth against variants for a year after infection.
    • Unlike after vaccination, the memory B cells formed after natural infection are more likely to make antibodies that block immune-evading variants.

     

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  • [pib] India’s First Banni Buffalo IVF Calf Born

    With the birth of first IVF calf of a Buffalo breed namely Banni in the country, India’s Ovum Pick-Up (OPU) – IVF work has reached to next level.

    Banni Buffalo

    • Banni buffaloes are also known as “Kutchi” or “Kundi”.
    • The breeding tract includes the Banni area of Kutchchh district of Gujarat.
    • The breed is maintained mostly by Maldharis under locally adapted typical extensive production system in its breeding tract.

    What makes them unique?

    • Banni buffaloes are trained to graze on Banni grassland during night and brought to the villages in the morning for milking.
    • This traditional system of buffalo rearing has been adapted to avoid the heat stress and high temperature of the day.
    • It has unique qualities of adaptation such as the ability to survive water scarcity conditions, to cover long distances during periods of drought and disease resistance.

    Indigenous buffalo breeds in India

    S. No. Breed Breeding state
    1 Banni Gujarat
    2 Bargur Tamil Nadu
    3 Bhadawari Uttar Pradesh and Madhya Pradesh
    4 Chhattisgarhi Chhattisgarh
    5 Chilika Odisha
    6 Gojri Himachal Pradesh and Punjab
    7 Jaffarabadi Gujarat
    8 Kalahandi Odisha
    9 Luit (Swamp) Assam
    10 Marathwadi Maharashtra
    11 Mehsana Gujarat
    12 Murrah Haryana and Delhi
    13 Nagpuri Maharashtra
    14 Nili Ravi Punjab
    15 Pandharpuri Maharashtra
    16 Surti Gujarat
    17 Toda Tamil Nadu

     

     

     

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    Back2Basics: In-vitro fertilization (IVF)

    • IVF is a type of assisted reproductive technology used for infertility treatment and gestational surrogacy.
    • A fertilised egg may be implanted into a surrogate’s uterus, and the resulting child is genetically unrelated to the surrogate.
    • Some countries have banned or otherwise regulate the availability of IVF treatment, giving rise to fertility tourism.
    • Restrictions on the availability of IVF include costs and age, in order for a woman to carry a healthy pregnancy to term.
    • IVF is generally not used until less invasive or expensive options have failed or been determined unlikely to work.

    IVF process

    • IVF is a process of fertilization where an egg is combined with sperm outside the body, in vitro (“in glass”).
    • The process involves monitoring and stimulating a female ovulatory process, removing an ovum or ova (egg or eggs) from the female ovaries and letting sperm fertilise them in a liquid in a laboratory.
    • After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is implanted in the same or another female uterus, with the intention of establishing a successful pregnancy.

     

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  • Mosquirix: First malaria vaccine to get WHO nod

    In a historic move, the World Health Organization (WHO) has endorsed the first anti-malarial vaccine, as mankind enters a key turning point in a battle waged relentlessly over decades between man and mosquito, the vector.

    Mosquirix

    • RTS,S/ASO1 (RTS.S), trade name Mosquirix acts against P. falciparum, the most deadly malaria parasite globally, and the most prevalent in Africa.
    • The vaccine was able to prevent approximately 4 in 10 cases of malaria over a 4-year period in Africa.
    • This is the first malaria vaccine that has completed the clinical development process.
    • It is also the first malaria vaccine to be introduced by three national ministries of health through their childhood immunization programs — more than 800,000 children in Ghana, Kenya, and Malawi.
    • have been vaccinated, and are benefiting from the added protection provided by the vaccine as part of a pilot program.

    How the vaccine can help?

    • WHO’s recommendation is based on the advice of its two global advisory bodies, one for immunization and the other for malaria.
    • WHO has recommended that in the context of comprehensive malaria control, the RTS,S/AS01 malaria vaccine be used for the prevention of P. falciparum malaria in children living in regions with moderate to high transmission as defined by it.
    • The malaria vaccine should be provided in a schedule of 4 doses in children from 5 months of age for the reduction of malaria disease and burden.

    Back2Basics: Malaria

    • Malaria is caused by the bite of the female Anopheles mosquito if the mosquito itself is infected with a malarial parasite.
    • There are five kinds of malarial parasites — Plasmodium falciparum, Plasmodium vivax (the commonest ones), Plasmodium malariae, Plasmodium ovale and Plasmodium knowlesi.
    • Therefore, to say that someone has contracted the Plasmodium ovale type of malaria means that the person has been infected by that particular parasite.
    • Malaria is treated with prescription drugs to kill the parasite. Chloroquine is the preferred treatment for any parasite that is sensitive to the drug.

    Countries that have eliminated malaria

    • Globally, the elimination net is widening, with more countries moving towards the goal of zero malaria.
    • In 2019, 27 countries reported fewer than 100 indigenous cases of the disease, up from 6 countries in 2000.
    • Countries that have achieved at least 3 consecutive years of zero indigenous cases of malaria are eligible to apply for the WHO certification of malaria elimination.
    • 11 countries have been certified as malaria-free: United Arab Emirates (2007), Morocco (2010), Turkmenistan (2010), Armenia (2011), Sri Lanka (2016), Kyrgyzstan (2016), Paraguay (2018), Uzbekistan (2018), Algeria (2019), Argentina (2019), and El Salvador (2021).

    Burden of Malaria in India

    • In 2018, the National Vector-borne Disease Control Programme (NVBDCP) estimated that approximately 5 lakh people suffered from malaria.
    • 63% of the cases were of Plasmodium falciparum.
    • The recent World Malaria Report 2020 said cases in India dropped from about 20 million in 2000 to about 5.6 million in 2019.

     

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  • Physiology Nobel for work on temperature and touch

     

    U.S. scientists David Julius and Ardem Patapoutian have won the Nobel Medicine Prize for discoveries on receptors for temperature and touch.

    Who are the Laureates?

    • David Julius and Ardem Patapoutian, working independently in the United States, made a series of discoveries in the late 1990s and early 2000s.
    • They figured out the touch detectors in our body and the mechanism through which they communicate with the nervous system to identify and respond to a particular touch.

    What did they discover?

    • They discovered the molecular sensors in the human body that are sensitive to heat, and to mechanical pressure, and make us “feel” hot or cold, or the touch of a sharp object on our skin.
    • n 1997, Dr. Julius and his team published a paper in Nature detailing how capsaicin, or the chemical compound in chili peppers, causes the burning sensation.
    • They created a library of DNA fragments to understand the corresponding genes and finally discovered a new capsaicin receptor and named it TRPV1.
    • This discovery paved the way for the identification of many other temperature-sensing receptors.
    • They identified another new receptor called TRPM8, a receptor that is activated by cold. It is specifically expressed in a subset of pain-and-temperature-sensing neurons.
    • They identified a single gene PIEZO2, which when silenced made the cells insensitive to the poking. They named this new mechanosensitive ion channel Piezo1.

    How do they work?

    • The human ability to sense heat or cold and pressure is not very different from the working of the many detectors that we are familiar with.
    • When something hot, or cold, touches the body, the heat receptors enable the passage of some specific chemicals, like calcium ions, through the membrane of nerve cells.
    • It’s like a gate that opens up on a very specific request. The entry of the chemical inside the cell causes a small change in electrical voltage, which is picked up by the nervous system.
    • There is a whole spectrum of receptors that are sensitive to different ranges of temperature.
    • When there is more heat, more channels open up to allow the flow of ions, and the brain is able to perceive higher temperatures.

    Therapeutic implications

    • Breakthroughs in physiology have often resulted in an improvement in the ability to fight diseases and disorders. This one is no different.
    • There are receptors that make us feel pain. If these receptors can suppress, or made less effective, the person had felt less pain.
    • Chronic pain is present is a number of illnesses and disorders. Earlier, the experience of pain was a mystery.
    • But as we understand these receptors more and more, it is possible that we gain the ability to regulate them in such a way that the pain is minimized.

    [Note: We will compile all Nobel Prizes into a single post once all are awarded.]

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  • What is Meningitis?

    The World Health Organization (WHO) has launched the first-ever global strategy to defeat meningitis, a debilitating disease that kills hundreds of thousands of people each year.

    What is Meningitis?

    • Meningitis is an inflammation of the meninges, the membranes that cover the brain and spinal cord.
    • People of any age can get meningitis.

    What Causes Meningitis?

    • Most cases are caused by bacteria or viruses, but some can be due to certain medicines or illnesses.
    • Meningitis is usually caused by a viral infection but can also be bacterial or fungal.
    • Both kinds of meningitis spread like most other common infections do — someone who’s infected touches, kisses, or coughs or sneezes on someone who isn’t infected.
    • Bacterial meningitis is rare, but is usually serious and can be life-threatening if not treated right away.
    • Viral meningitis (also called aseptic meningitis) is more common than bacterial meningitis and usually less serious.
    • Many of the viruses that cause meningitis are common, such as those that cause colds, diarrhea, cold sores, and the flu.

    What Are the Signs & Symptoms of Meningitis?

    • Meningitis symptoms vary, depending on the person’s age and the cause of the infection.
    • The first symptoms can come on quickly or start several days after someone has had a cold, diarrhea, vomiting, or other signs of an infection.

    Common symptoms include:

    • fever
    • lack of energy
    • irritability
    • headache
    • sensitivity to light
    • stiff neck
    • skin rash

    Treatment

    • Several vaccines protect against meningitis, including meningococcal, Haemophilus influenzae type b and pneumococcal vaccines.
    • If dealt with quickly, meningitis can be treated successfully.

     

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