Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Drug Toxicity: Allergic Reactions

Drug Toxicity: Allergic Reactions

Drug-related allergies are immune-mediated responses triggered by the administration of pharmacological agents. These hypersensitivity reactions are classified based on the immune mechanisms involved. The four primary types—Type I, II, III, and IV—are mediated by different immunological pathways and exhibit distinct clinical manifestations.Type I Hypersensitivity/ IgE-Mediated Reactions: Immunoglobulin E (IgE) immediately mediates Type I hypersensitivity reactions. Upon initial exposure to a...

Physical Properties of Amines

Physical Properties of Amines

Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.

Aryldiazonium Salts to Azo Dyes: Diazo Coupling

Aryldiazonium Salts to Azo Dyes: Diazo Coupling

The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.

Drug Toxicity: Dose-Dependent Reactions

Drug Toxicity: Dose-Dependent Reactions

Drug toxicities can be stratified into pharmacological, pathological, or genotoxic based on their mechanisms. The incidence and severity of these toxicities generally increase with the drug's concentration in the body and exposure time.Pharmacological toxicity is evident when the therapeutic effects of drugs overshoot into adverse reactions in a predictable, dose-dependent manner. Central nervous system (CNS) depression from barbiturates is a classic example, with effects escalating from...

Hypersensitivities

Hypersensitivities

Hypersensitivity, also known as a hypersensitivity reaction or allergic reaction, is a condition where the body's immune system reacts abnormally to a foreign substance. Such substances, that cause hypersensitivity are referred to as an allergen, could be something typically harmless to most people, like pollen or certain foods.
Types of Hypersensitivities
Hypersensitivity reactions are categorized into four types: Type 1, Type 2, Type 3, and Type 4. Each type has a distinct mechanism...

Hypersensitivity Reactions: Delayed Hypersensitivity Reactions

Hypersensitivity Reactions: Delayed Hypersensitivity Reactions

Delayed-Type Hypersensitivity (DTH), or Type IV hypersensitivity, is a cell-mediated immune response. It occurs when T cells, rather than antibodies, mediate a reaction to specific antigens. It is characterized by a delayed onset (1-2 days) and involves the recruitment of macrophages to the inflammation site.The initiation of a DTH response begins with the sensitization of T cells. During this phase, which lasts at least 1-2 weeks, antigen-specific T cells are activated, clonally expanded, and...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

The influence of the lipid composition on drug permeation though stratum corneum-mimicking biomimetic artificial barriers.

International journal of pharmaceutics·2026

Same author

A new standard framework for dermal exposure assessment.

Annals of work exposures and health·2026

Same author

Outcomes and prognostic factors in patients with systemic mastocytosis and an associated myeloid neoplasm: an international ECNM registry study.

Journal of hematology & oncology·2026

Same author

Living in the sun's shadow: Skin cancer and albinism in Senegal.

JAAD international·2026

Same author

Clinical and Mechanistic Evidence for Comano Thermal Water: A Narrative Review.

International journal of molecular sciences·2026

Same author

Lung Cancer Screening in a Population from Northeast Italy Exposed to Both Asbestos and Smoking: A Cost-Effectiveness Analysis.

Journal of clinical medicine·2026

Search research articles

Related Experiment Video

Updated: Jun 7, 2026

Contact Hypersensitivity as a Murine Model of Allergic Contact Dermatitis

Contact Hypersensitivity as a Murine Model of Allergic Contact Dermatitis

Published on: September 26, 2022

p-Phenylenediamine sensitization and occupation.

Andrea Malvestio¹, Massimo Bovenzi, Mohamad Hoteit

¹Clinical Unit of Occupational Medicine, University of Trieste, 34129 Trieste, Italy.

Contact Dermatitis

|November 3, 2010

Summary

p-Phenylenediamine (PPD) sensitization is linked to various occupations, including hairdressing, beauty, driving, and cleaning. Reducing exposure to PPD and related substances is crucial for at-risk workers.

More Related Videos

A Mouse Ear Model for Allergic Contact Dermatitis Evaluation

A Mouse Ear Model for Allergic Contact Dermatitis Evaluation

Published on: March 24, 2023

Assessment of the Cytotoxic and Immunomodulatory Effects of Substances in Human Precision-cut Lung Slices

Assessment of the Cytotoxic and Immunomodulatory Effects of Substances in Human Precision-cut Lung Slices

Published on: May 9, 2018

Related Experiment Videos

Last Updated: Jun 7, 2026

Contact Hypersensitivity as a Murine Model of Allergic Contact Dermatitis

Contact Hypersensitivity as a Murine Model of Allergic Contact Dermatitis

Published on: September 26, 2022

A Mouse Ear Model for Allergic Contact Dermatitis Evaluation

A Mouse Ear Model for Allergic Contact Dermatitis Evaluation

Published on: March 24, 2023

Assessment of the Cytotoxic and Immunomodulatory Effects of Substances in Human Precision-cut Lung Slices

Assessment of the Cytotoxic and Immunomodulatory Effects of Substances in Human Precision-cut Lung Slices

Published on: May 9, 2018

Area of Science:

Dermatology
Occupational Medicine
Toxicology

Background:

p-Phenylenediamine (PPD) is a potent sensitizer causing delayed-type skin reactions.
Occupational and non-occupational exposures to PPD are significant public health concerns.

Purpose of the Study:

To determine the prevalence of PPD sensitization in patients with suspected allergic contact dermatitis in northeastern Italy.
To identify occupations associated with an increased risk of PPD sensitization.

Main Methods:

Patch testing was performed on 14,464 patients with suspected allergic dermatitis.
Multivariate logistic regression analysis was used to assess the association between PPD sensitization and occupation.

Main Results:

PPD sensitization was significantly associated with hairdressing and beauty occupations for both sexes.
In women, higher PPD sensitization rates were observed in professional drivers, barmaids, and cleaners.
In men, elevated sensitization was noted in bakers, waiters, household workers, and printers.

Conclusions:

Several occupations present a heightened risk for developing PPD sensitization.
Minimizing exposure to PPD and cross-reacting substances in these occupations is essential for prevention.