Reduced ability to produce reflex-evoked neurogenic inflammation, a sign of decreased defense against COVID-19 infection?

Background: A histamine skin prick test (SPT) generally evokes a wheal and a flare. The present study was initiated by an observation that histamine did not evoke a flare around a wheal in the skin of an 86-year-old man. Could that be of relevance to the findings that old men are prone to a more severe COVD-19 infection with a higher mortality than young ones?

Materials And Methods: Histamine SPT was performed on the forearm of six old men, all above the age of 80.

Re-sensitization of desensitized histamine H1 receptors in the human skin takes more than 18 hours.

Background: It is known since the time of testing histamine on pieces of guinea pig's jejunum that histamine receptors can develop insensitivity. The aim was to find evidence for desensitization of histamine H1 receptors in the human skin in vivo and, if found, to study the time for such receptors to regain normal sensitivity.

Materials And Methods: A skin prick test with histamine (10 mg mL ) was set in areas where a large histamine wheal was evoked 2, 6, 18, 24 or 72 hours earlier.

Colour change in the human histamine wheal made visible by LYYN: a technique to enhance colour differences.

Background: Colour differences in photographs can be enhanced using a digital image-processing technique called LYYN.

Objective: To investigate colour changes in the histamine wheal after skin prick tests (SPTs).

Methods: Histamine SPTs were performed on the forearm of six medical students, and the reactions of the skin were photographed every 2min for 30min.

Hoarseness as a sign of possible nonspecific mucosal hyperreactivity in vocal tract.

The aim of the present paper was to evaluate the possible impact of methacholine challenge on the voice and vocal tract in 10 patients reporting hoarseness due to presumable hyperreactivity to some environmental factors. Ten age and gender-matched healthy subjects served as controls. Methacholine was used for hypersensitivity challenge and saline solution (0.

Neurotransmitter candidates in the vomeronasal organ of the rat.

Conclusion: The rich supply of nerve fibres containing neurotransmitters, particularly those containing SP and CGRP, is suggested to be a prerequisite for the recognition of chemical irritants as part of a chemical sense.

Objective: The present study was designed to examine the distribution of different neurotransmitter candidates in the vomeronasal organ (VNO) of rats.

Materials And Methods: The distribution of neurotransmitter candidates was studied in the vomeronasal organ of the rat using immunocytochemistry.

Allergic rhinitis and atopy in 18-year-old students.

Background: The aim of this study was to investigate the prevalence of allergic rhinitis and atopy in adolescents and whether air pollution in their schools contributed to allergic sensitization.

Methods: Analyses were performed in 1992-1994 on 511 18-year-old students at four schools and on the indoor air and floor dust of their classrooms. The students underwent skin-prick tests (SPTs) and a nasal lavage and answered a computer-based questionnaire containing questions on allergy and nasal symptoms.