Subject: Biotech and Medical Sciences

Why in the news?

• Magnetic Resonance Imaging (MRI) revolutionized medical diagnostics, offering non-invasive insights into soft tissues.
• The pioneering efforts of Paul Lauterbur and Peter Mansfield led to its commercialization, earning them the Nobel Prize in Medicine in 2003.

What is MRI?

• Magnetic resonance imaging (MRI) is a non-invasive diagnostic procedure used to obtain detailed images of soft tissues within the body.
• It is particularly valuable for imaging sophisticated structures like the brain, cardiovascular system, spinal cord, joints, muscles, liver, and arteries.
• MRI is instrumental in diagnosing and monitoring various conditions, including cancer, neurological disorders (such as Alzheimer’s and stroke), and cardiovascular diseases.
• Functional MRI (fMRI) can also assess brain activity by monitoring changes in blood flow.

Working Principle:

• MRI utilizes the magnetic properties of hydrogen atoms (one proton with one electron around it), which are abundant in water and fat molecules found throughout the body.
• The MRI machine generates a powerful magnetic field, aligning hydrogen atoms within the body.
• Radiofrequency pulses are then applied, causing hydrogen atoms to absorb energy and emit signals.
• These emitted signals are detected by sensors and processed by a computer to create detailed images of the body’s internal structures.

Components of an MRI Machine:

The MRI machine consists:

• Superconducting Magnet: Large magnet (superconducting magnet) that produces a powerful and stable magnetic field.
• Gradient Coils: Gradient magnets produce smaller magnetic fields with varying strengths and directions, allowing for precise imaging of specific body areas.
• Radiofrequency Coils: This emit radiofrequency pulses to excite hydrogen atoms in the body. The frequency of pulse the ‘excess’ atoms have to absorb is called the Larmor frequency.
• Detectors: It capture emitted signals from hydrogen atoms and convert them into image data for analysis.

Advantages of MRI:

• High-Resolution Imaging: MRI offers high-resolution imaging with excellent tissue contrast, allowing for accurate diagnosis and treatment planning.
• Versatile Viewing Angles: It can visualize structures from various angles without the need for repositioning, providing comprehensive information.
• Safety and Non-Invasiveness: MRI scans are non-invasive and do not involve ionizing radiation, making them safe for repeated use.
• Enhanced Image Quality: Contrast agents can enhance image quality by highlighting specific tissues or abnormalities.

Limitations of MRI:

• High Costs: MRI machines are expensive to purchase and maintain, resulting in high healthcare costs for patients.
• Requirement for Patient Stillness: Patients undergoing MRI scans must remain still for extended periods to prevent image distortion, which can be challenging for some individuals.
• Discomfort or Anxiety: The strong magnetic fields and loud noises produced during MRI scans may cause discomfort or anxiety for patients.
• Limitations with Metallic Implants: Certain metallic implants or objects can interfere with MRI scans, limiting their use in individuals with such implants.

Why in the news?

• Researchers at the Fred Hutchinson Cancer Center in the US have identified specific subtypes of Fusobacterium nucleatum associated with colorectal cancer (CRC) tumors.
• These subtypes, particularly Fusobacterium nucleatum animalis (Fna), have been found in relatively higher quantities in CRC tumors.

About Fusobacterium nucleatum

• Fusobacterium nucleatum is a species of bacteria commonly found in the human mouth.
• It is a gram-negative anaerobic bacterium, meaning it does not require oxygen for growth.
• While typically residing in the oral cavity, it has been associated with various diseases and conditions, including periodontal diseases and colorectal cancer.

Association with Colorectal Cancer (CRC):

• In cases of colorectal cancer (CRC), Fusobacterium nucleatum has been found within tumors in the gut.
• Studies have shown that this bacterium can aid cancer cells in evading the immune system and promoting metastasis, or the spread of cancer to other parts of the body.
• Its presence in CRC tumors has led to investigations into its potential role in the development and progression of colorectal cancer.

Impact:

• Assisting cancer cells in evading the immune system.
• Promoting inflammation and creating an environment conducive to tumor growth.
• Facilitating metastasis by interacting with cancer cells and promoting their spread to other tissues.

Why in the news?

• The Kerala government disclosed the re-emergence of West Nile fever cases in Thrissur, Malappuram, and Kozhikode districts.
• West Nile fever was first detected in Kerala in 2011, with a fatal case recorded in 2019 involving a six-year-old from Malappuram.

What is West Nile Fever?

• West Nile fever is caused by a West Nile Virus (WNV) transmitted through bites from infected Culex mosquitoes.
• The WNV is a mosquito-borne, single-stranded RNA virus.
• According to the WHO, it is a member of the flavi-virus genus and belongs to the Japanese Encephalitis antigenic complex of the family Flaviviridae.

How does it spread?

• It is transmitted by infected mosquitoes between and among humans and animals, including birds, which are the reservoir host of the virus.
• Mosquitoes become infected when they feed on infected birds, which circulate the virus in their blood for a few days.
• The virus eventually gets into the mosquito’s salivary glands.
• During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness.
• WNV can also spread through blood transfusion, from an infected mother to her child, or through exposure to the virus in laboratories.
• It is not known to spread by contact with infected humans or animals.

Symptoms of WNV infection:

• The disease is asymptomatic in 80% of the infected people.
• The rest develop what is called the West Nile fever or severe West Nile disease.
• In these 20% cases, the symptoms include fever, headache, fatigue, body aches, nausea, rash, and swollen glands.

Back2Basics: Type of Viruses 

Why in the news?

Every year on May 5, pulmonary hypertension organizations and groups around the world participate in World Pulmonary Hypertension Day.

What is Pulmonary Hypertension?

• Pulmonary hypertension (PH) is a condition characterized by high blood pressure in the pulmonary arteries, which are the blood vessels that carry blood from the heart to the lungs.
• This elevated pressure in the pulmonary arteries can lead to various symptoms and complications, affecting the heart’s ability to pump blood effectively to the lungs and the rest of the body.

Here are some key aspects of pulmonary hypertension:

Causes:

1. Idiopathic Pulmonary Arterial Hypertension (IPAH): In many cases, the exact cause of pulmonary hypertension is unknown, and it is referred to as idiopathic. IPAH is a subtype of PH without an identifiable cause.
2. Secondary Pulmonary Hypertension: PH can also develop secondary to other underlying conditions, including:
   • Chronic obstructive pulmonary disease (COPD)
   • Interstitial lung disease
   • Sleep apnea
   • Connective tissue diseases such as scleroderma and lupus
   • Congenital heart diseases
   • HIV infection
   • Liver disease (cirrhosis)
3. Genetic Factors: Some forms of PH may have a genetic component, with mutations in certain genes predisposing individuals to the condition.

Features:

• Symptoms: Symptoms of pulmonary hypertension may include:

1. 1. • Shortness of breath, especially during physical activity
      • Fatigue
      • Chest pain or pressure
      • Dizziness or fainting spells
      • Swelling in the ankles and legs (edema)
      • Bluish lips or skin (cyanosis)

• Diagnostic Tests: Diagnosis of pulmonary hypertension typically involves a combination of medical history review, physical examination, and diagnostic tests, including:

1. 1. • Echocardiogram (ECG)
      • Right heart catheterization
      • Pulmonary function tests
      • Chest X-ray
      • CT scan or MRI of the chest
      • Blood tests

• Treatment: Treatment for pulmonary hypertension aims to relieve symptoms, improve quality of life, and slow disease progression. Treatment options may include:

1. • Medications such as vasodilators, endothelin receptor antagonists, and prostacyclin analogs
   • Oxygen therapy
   • Pulmonary rehabilitation
   • Surgery or a lung transplant in severe cases

Why in the news?

• Researchers from Kerala reported 15 cases of Membranous Nephropathy (MN) linked to the regular application of fairness creams.
• These creams contained high levels of mercury, sometimes exceeding the safe limit by 10,000 times.

Mercury Contamination in Hair Cream

• Blood and urine screenings of affected individuals unveiled alarmingly high levels of mercury, a well-known toxic element.
• The fairness creams contained mercury levels up to 10,000 times above the permissible limit of 1 ppm under Minamata Convention (2013).
• Most cases were PLA2R (phospholipase A2 receptor) negative, indicating a different cause.
• Cases of MN linked to Neural epidermal growth factor-like protein 1 (NELL-1) have been identified.
• NELL-1 has been associated with MN caused by traditional medicines containing high mercury levels.

Understanding Membranous Nephropathy

• Membranous Nephropathy (MN) is a nephrotic syndrome, characterized by excessive protein leakage into urine, eventually leading to kidney failure. Symptoms such as fatigue, edema, and proteinuria were found to have a history of regular fairness cream usage.

Impact of Mercury:

• Mercury in fairness creams inhibits melanin formation, resulting in lighter skin. Consumers perceive higher mercury levels as more effective for skin whitening.
• Mercury, a potent heavy metal found in these creams, penetrates the body through various channels, including sweat glands and hair follicles, causing systemic toxicity.
• Chronic exposure to mercury can result in kidney damage, neurological disorders, and a myriad of other health complications.

Why in the news?

After multiple rounds of screening, researchers have identified an antibody, 95Mat5 that showed promising results in making a potent antidote against various snake venoms.

What is 95Mat5?

• 95Mat5 is a universal antivenom developed to neutralize the toxins present in snake venoms.
• Development Process:

1. The scientists first synthesized variants of a toxin called long-chain 3FTxs (3FTx-L), which are found in the venoms of various snakes, including cobras, kraits, mambas, and monocled cobras.
2. They then screened billions of human antibodies expressed on the surface of yeast cells to find antibodies that bound best to the synthesized toxins.
3. After multiple rounds of screening, they identified a shortlist of antibodies that broadly reacted with most of the 3FTx variants used in the study.
4. The selected antibodies were further tested in vitro in human cells to determine which ones could best neutralize the toxins.

Mechanism of Action

• 95Mat5 specifically targets α-neurotoxins, which are a specific class of 3FTxs that prevent nerve and muscle cells from responding to acetylcholine, a neurotransmitter involved in carrying messages from neurons to muscles.
• By binding to the toxins, 95Mat5 prevents toxins from interacting with the receptors in human nerve and muscle cells, thereby blocking their ability to induce paralysis and other deadly effects.
• In animal experiments, 95Mat5 demonstrated efficacy in neutralizing the toxins present in the venoms of various snake species, protecting the animals from death.

Why in the news?

Understanding and managing Glycemic Index (GI) in diets is crucial for promoting long-term health and mitigating the risk of chronic diseases.

What is Glycemic Index (GI)?

• Prof. David Jenkins of the University of Toronto introduced Glycemic Index (GI) in 1981.
• GI measures how quickly a food raises blood glucose levels compared to a reference food, typically glucose or white bread, which is assigned a value of 100.

GI Classification and Glycemic Load (GL):

• Multiplying GI by the amount of carbohydrate consumed gives the Glycemic Load (GL).
• Accordingly, foods are classified as:

1. Low GI (below 55): Brown rice, steel-cut oats, legumes (such as lentils and chickpeas), most fruits (like apples, berries, and oranges), vegetables, nuts, and seeds.
2. Medium GI (56-69): Whole wheat products, such as whole wheat bread and pasta, some types of rice (like basmati rice), and certain fruits like pineapple and mango.
3. High GI (70 or above): Refined carbohydrates and sugary foods such as white rice, white bread, refined flour products, potatoes, sweetened drinks (like soda), candies, cookies, and sugary snacks.

Debate and Perspectives:

• The Prospective Urban Rural Epidemiology (PURE) study, spanning 20 countries including India, revealed the link between high GI diets and cardiovascular events and mortality.
• Evidence supports the association between high GI diets and increased risk of type 2 diabetes, cardiovascular disease, and mortality.

Relevance to India

• In South Asia, where diets are rich in high GI foods like white rice, efforts to reduce GI and GL are crucial.
• Lowering GI and GL can help prevent not only diabetes but also premature cardiovascular disease, which is prevalent in India.

Why in the news?

• A significant health concern in Tamil Nadu is found through ingestion of Rat poison containing Yellow Phosphorus, leading to liver toxicity.
  • Since December 2017, the team at CMC Vellore introduced Plasma Exchange, (a cost-effective treatment) for acute liver failure caused by rat poison ingestion.

What is Plasma Therapy (Plasmapheresis)?

• Plasma exchange, also known as plasmapheresis, is a medical procedure used to treat various conditions by removing and replacing plasma from the blood.
• During Plasma Exchange, the patient’s blood is circulated through a machine that separates plasma from other blood components, such as red and white blood cells and platelets.

Working procedure:

• The plasma, which may contain harmful substances or antibodies, is discarded.
• The remaining blood components are mixed with replacement plasma or a plasma substitute and returned to the patient’s bloodstream.

Usage of Plasmapheresis:

• In Autoimmune diseases: Conditions such as Guillain-Barre syndrome, myasthenia gravis, systemic lupus erythematosus, and certain forms of vasculitis.
• In Neurological disorders: Conditions such as multiple sclerosis, chronic inflammatory demyelinating polyneuropathy, and certain types of encephalitis.
• In Toxicological emergencies: Poisoning or overdose with substances such as drugs, chemicals, or toxins that can be removed from the bloodstream through plasma exchange.

Benefits observed in TN’s Case

• The treatment significantly improved survival rates, with 63.9% of patients treated in 2022-2023 successfully discharged.
• Retrospective studies at CMC Vellore demonstrated promising outcomes, with survival rates of 75% among children and 80.2% among adults treated with plasma exchange.