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Related Concept Videos

Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
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Hemoperfusion and hemofiltration are critical techniques in medical treatments to eliminate accumulated drugs, metabolites, and electrolytes from the bloodstream. These methods are particularly vital in cases of accidental poisoning and drug overdose.Hemoperfusion involves passing blood through an adsorbent material to remove unwanted substances. The main adsorbents used in hemoperfusion include activated charcoal and Amberlite resins. Activated charcoal can adsorb both polar and nonpolar...
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Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.

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Novel Protocol for Generating Physiologic Immunogenic Dendritic Cells
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Extracorporeal photochemotherapy.

Akira Maeda1

  • 1Department of Geriatric and Environmental Dermatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. amaeda@med.nagoya-cu.ac.jp

Journal of Dermatological Science
|April 17, 2009
PubMed
Summary
This summary is machine-generated.

Extracorporeal photochemotherapy (ECP) uses ultraviolet A radiation and a photosensitizer to modulate the immune system, offering therapeutic benefits for various diseases with minimal side effects. Further research is needed to fully understand its complex mechanisms of action.

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Area of Science:

  • Immunology
  • Dermatology
  • Photomedicine

Background:

  • Extracorporeal photochemotherapy (ECP) is an established treatment for cutaneous T-cell lymphoma, graft-versus-host disease, and autoimmune disorders.
  • The procedure involves reinfusing leukocytes treated with 8-methoxypsoralen (8-MOP) and ultraviolet A (UVA) radiation.
  • Despite its clinical use, the precise immunomodulatory mechanisms underlying ECP's efficacy remain incompletely understood.

Purpose of the Study:

  • To elucidate the underlying mechanisms of action for extracorporeal photochemotherapy (ECP).
  • To investigate how ECP induces both anti-tumor immunity and immune tolerance.

Main Methods:

  • The study reviews existing literature on ECP, focusing on its effects on immune cells and pathways.
  • Analysis of how ECP modulates regulatory T cells and other immune cell populations.

Main Results:

  • ECP demonstrates long-lasting immunomodulatory effects despite treating a small percentage of circulating cells.
  • Emerging evidence suggests ECP downregulates immune responses and induces tolerance via regulatory T cells.
  • Other immune cells are also implicated in ECP's mechanism.

Conclusions:

  • Immune tolerance is the most probable mechanism for ECP's efficacy in autoimmune disorders.
  • The dual action of ECP in activating anti-tumor immunity and inducing tolerance requires further investigation.
  • Additional research is essential to fully delineate the intricate mechanisms of ECP.