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Antifungal Agents

Antifungal Agents

Amphotericin B is a broad-spectrum antifungal agent that exploits structural differences between fungal and mammalian cell membranes. Its amphipathic structure—featuring a hydrophobic polyene-lactone ring and a hydrophilic region containing mycosamine and carboxylic acid groups—enables selective binding to ergosterol, a sterol predominantly found in fungal plasma membranes. This selective interaction underlies the drug’s antifungal activity, although weak binding to cholesterol contributes to...

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Indirect-acting cholinergic agonists, or anticholinesterases, enhance the body's cholinergic activity by inhibiting acetylcholine's breakdown. They are categorized as reversible or irreversible agents based on their mechanism of action. They are further classified into short-acting, intermediate-acting, and long-acting agents based on their duration of action.
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...

Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship

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Indirect-acting cholinergic agonists are agents that interact with the acetylcholinesterase enzyme in the synaptic cleft, preventing the breakdown of acetylcholine into choline and acetate. Consequently, the concentration of acetylcholine in the synaptic cleft increases. These agonists can be classified into reversible and irreversible inhibitors based on their duration of action.
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...

Cholinergic Antagonists: Pharmacokinetics

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Cholinergic antagonists—such as antimuscarinics—are available in oral, topical, ocular, parenteral, and inhalational formulations. Most antimuscarinics are oral formulations, while scopolamine is available as a topical patch, and ipratropium and tiotropium are available as inhalation aerosols or powders. Atropine, tropicamide, and cyclopentolate are topically instilled in the eye. Most antimuscarinics are lipid-soluble and readily absorbed from the gastrointestinal tract and the conjunctiva.

Indirect-Acting Cholinergic Agonists: Mechanism of Action

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Indirect-acting cholinergic agonists work by interacting with an enzyme called acetylcholinesterase (AChE) in the synaptic cleft. They can be reversible or irreversible inhibitors and have different effects on the enzyme.
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Related Experiment Video

Updated: May 31, 2026

Measurement of Chitinase Activity in Biological Samples

Measurement of Chitinase Activity in Biological Samples

Published on: August 22, 2019

Chitinolytic activity in nasal polyps.

Seong Kook Park¹, Kyung Wook Heo, Dae Young Hur

¹Department of Otorhinolaryngology-Head and Neck Surgery, Inje University, College of Medicine, Busan Paik Hospital, Busan, Korea. sinus4@paik.ac.kr

American Journal of Rhinology & Allergy

|June 30, 2011

Summary

This summary is machine-generated.

Increased chitinase activity, including acidic mammalian chitinase (AMCase) and chitotriosidase (ChT), was found in nasal polyps. These enzymes are coexpressed in monocytes within nasal polyp tissue, suggesting a role in pathogenesis.

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Area of Science:

Immunology
Biochemistry

Background:

Chitin acts as a recognition element for innate immune cell infiltration in allergic and immune responses.
Vertebrate chitinases, such as acidic mammalian chitinase (AMCase) and chitotriosidase (ChT), negatively regulate chitin-mediated processes.
AMCase and ChT possess chitinolytic activity.

Purpose of the Study:

To quantify AMCase and ChT activities in nasal polyps (NPs).
To investigate the in situ localization of AMCase and ChT within NP tissue.

Main Methods:

Chitinolytic activity assays were performed on NP and inferior turbinate tissue samples across various pH levels using a fluorogenic substrate.
Double immunofluorescent staining was employed on NP cryosections to determine the cellular localization of AMCase and ChT.

Main Results:

Nasal polyps exhibited significantly higher AMCase and ChT chitinolytic activity compared to inferior turbinate tissues.
Immunofluorescence revealed coexpression of AMCase and ChT in CD68-positive monocytes within the submucosa of NPs.
CD31-positive capillary endothelial cells did not express AMCase or ChT.

Conclusions:

Elevated chitinolytic activities of AMCase and ChT in NPs may contribute to their pathogenesis.
Inhibiting chitinolytic activity presents a potential novel therapeutic strategy for treating NPs.