Arava

Arava is a brand name for the drug leflunomide, which is primarily used to treat rheumatoid arthritis. It is classified as a disease-modifying antirheumatic drug (DMARD) and works by inhibiting the synthesis of pyrimidine, which is necessary for the proliferation of lymphocytes. This action helps to reduce inflammation and slow the progression of the disease.

Medical Uses

Arava is prescribed for the treatment of rheumatoid arthritis and psoriatic arthritis. It helps to alleviate symptoms such as joint pain, swelling, and stiffness. The drug is often used in patients who have not responded adequately to other DMARDs like methotrexate.

Mechanism of Action

Leflunomide, the active ingredient in Arava, inhibits the enzyme dihydroorotate dehydrogenase (DHODH), which is involved in the de novo synthesis of pyrimidine. By blocking this pathway, leflunomide reduces the proliferation of activated T cells and B cells, which are key players in the autoimmune response seen in rheumatoid arthritis.

Side Effects

Common side effects of Arava include diarrhea, nausea, hair loss, and rash. More serious side effects can include liver damage, lung disease, and severe infections. Regular monitoring of liver function and blood counts is recommended during treatment.

Contraindications

Arava is contraindicated in patients with severe liver impairment, pregnancy, and those with known hypersensitivity to leflunomide. Women of childbearing potential should use effective contraception during treatment and for a period after discontinuation due to the drug's long half-life.

Drug Interactions

Arava can interact with other medications, including warfarin, rifampin, and other DMARDs. These interactions can increase the risk of side effects or reduce the effectiveness of the treatments.

Monitoring

Patients on Arava should undergo regular monitoring, including liver function tests, complete blood counts, and blood pressure checks. This helps to identify any adverse effects early and manage them appropriately.

Discontinuation

Due to its long half-life, discontinuation of Arava may require a drug elimination procedure using cholestyramine or activated charcoal to accelerate the removal of leflunomide from the body.

Related Pages

• Rheumatoid arthritis
• Psoriatic arthritis
• Disease-modifying antirheumatic drug
• Methotrexate
• Lymphocyte
• T cell
• B cell
• Dihydroorotate dehydrogenase
• Pyrimidine

Engineered Monoclonal Antibodies

Diagram of engineered monoclonal antibodies

Engineered monoclonal antibodies are a class of biological therapies that are designed to target specific antigens on the surface of cells. These antibodies are produced using recombinant DNA technologies and are used in the treatment of various diseases, including cancer, autoimmune disorders, and infectious diseases.

Structure and Function

Monoclonal antibodies are composed of two identical heavy chains and two identical light chains, forming a Y-shaped molecule. The tips of the "Y" contain the antigen-binding sites, which are highly specific to the target antigen. This specificity allows monoclonal antibodies to bind to their target with high affinity, blocking or modulating the function of the antigen.

Types of Engineered Monoclonal Antibodies

There are several types of engineered monoclonal antibodies, each designed for specific therapeutic purposes:

• Chimeric antibodies: These antibodies are composed of murine (mouse) variable regions and human constant regions. They are less immunogenic than fully murine antibodies.

• Humanized antibodies: These antibodies are mostly human, with only the antigen-binding sites derived from murine sources. This reduces the risk of immune reactions.

• Fully human antibodies: These are entirely human in origin, produced using transgenic mice or phage display technologies.

• Bispecific antibodies: These antibodies are engineered to bind two different antigens simultaneously, offering unique therapeutic mechanisms.

Applications in Medicine

Engineered monoclonal antibodies have revolutionized the treatment of many diseases:

• Cancer therapy: Monoclonal antibodies can target specific tumor antigens, leading to direct tumor cell killing or recruitment of immune cells to attack the tumor.

• Autoimmune diseases: By targeting specific components of the immune system, monoclonal antibodies can reduce inflammation and tissue damage in diseases such as rheumatoid arthritis and multiple sclerosis.

• Infectious diseases: Monoclonal antibodies can neutralize pathogens or their toxins, providing passive immunity or enhancing the host's immune response.

Production

The production of engineered monoclonal antibodies involves several steps:

1. Antigen identification: The target antigen is identified and characterized. 2. Hybridoma technology: B cells from immunized animals are fused with myeloma cells to create hybridomas that produce the desired antibody. 3. Recombinant DNA technology: Genes encoding the antibody are cloned and expressed in suitable host cells, such as Chinese hamster ovary cells. 4. Purification and formulation: The antibodies are purified and formulated for clinical use.

Challenges and Future Directions

While engineered monoclonal antibodies have shown great promise, there are challenges such as high production costs, potential for immune reactions, and the development of resistance. Ongoing research aims to improve antibody design, reduce immunogenicity, and enhance therapeutic efficacy.

Related Pages

• Monoclonal antibody therapy
• Biopharmaceutical
• Immunotherapy
• Hybridoma technology

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