Phenylpropanolamine

Overview of Phenylpropanolamine

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

Phenylpropanolamine (PPA) is a sympathomimetic agent used as a decongestant and appetite suppressant. It is a member of the phenethylamine class and is structurally related to ephedrine and amphetamine.

Pharmacology

Phenylpropanolamine acts primarily as an alpha-adrenergic receptor agonist, leading to vasoconstriction and decreased nasal congestion. It also has some activity as a beta-adrenergic receptor agonist, which contributes to its effects on appetite suppression.

Medical Uses

Phenylpropanolamine was commonly used in over-the-counter cold medications and weight loss products. It was effective in reducing nasal congestion and suppressing appetite.

Safety and Regulation

In the early 2000s, concerns about the safety of phenylpropanolamine led to its withdrawal from the market in many countries. Studies indicated an increased risk of hemorrhagic stroke in women using the drug. As a result, the U.S. Food and Drug Administration (FDA) issued a public health advisory in 2000, recommending that consumers not use products containing phenylpropanolamine.

Current Status

Phenylpropanolamine is no longer available in the United States and many other countries for human use. However, it is still used in veterinary medicine, particularly for the treatment of urinary incontinence in dogs.

Mechanism of Action

Phenylpropanolamine works by stimulating the release of norepinephrine and dopamine from nerve terminals, which leads to increased adrenergic activity. This results in vasoconstriction and reduced blood flow to the nasal passages, alleviating congestion.

Side Effects

Common side effects of phenylpropanolamine include increased heart rate, elevated blood pressure, anxiety, dizziness, and insomnia. Due to its stimulant effects, it can also lead to tachycardia and hypertension.

History

Phenylpropanolamine was first introduced in the 1930s and became widely used in the 1970s and 1980s. Its popularity declined after safety concerns emerged, leading to regulatory actions in the 1990s and 2000s.

Also see

• Ephedrine
• Pseudoephedrine
• Amphetamine
• Sympathomimetic drug
• Decongestant

Phenylpropanolamine

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  Phenylpropanolamine

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  Phenylpropanolamine molecule ball

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Phenylpropanolamine

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  Phenylpropanolamine

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  Phenylpropanolamine molecule ball

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  Phenylpropanolamine spacefill