Validation of a simplified provocation instrument for diagnosis and threshold testing of symptomatic dermographism.

BACKGROUND: Symptomatic dermographism is a common urticarial condition, which requires determination of provocation thresholds to confirm diagnosis and allow physicians to individualize management and therapy for optimal control of symptoms. To determine provocation thresholds, we have developed a provocation test device, the FricTest(®) 4.0. This simple and inexpensive device, which is stroked across the skin to produce a response, consists of a flat plastic comb with four round-ended plastic pins, 3 mm in diameter, and of differing lengths. AIM: To validate the FricTest(®) 4.0 by comparison with FricTest 3.0 in determining provocation thresholds in symptomatic dermographism, METHODS: Dermal provocation with the FricTest 4.0 and FricTest 3.0 was performed in parallel on the volar forearm of 30 patients with symptomatic dermographism and 30 healthy controls. The widths of the resulting weals were measured, and weals with a width of ≥ 3 mm were considered positive. Accompanying pruritus was assessed using a 10-point verbal rating scale. RESULTS: All 30 patients with symptomatic dermographism, but none of the healthy volunteers, showed positive responses to provocation with the strongest trigger strength, showing that FricTest(®) 4.0 has 100% sensitivity and specificity for diagnosing symptomatic dermographism. Quantitatively, both devices were similar in the number of patients who responded positively to different pin lengths. Results for pruritus were also similar with both instruments. CONCLUSIONS: The FricTest 4.0 is a simple and inexpensive instrument for determining provocation thresholds in patients with symptomatic dermographism. It should find a place in both routine clinical investigation and in therapeutic trials.

An improved Peltier effect-based instrument for critical temperature threshold measurement in cold- and heat-induced urticaria.

BACKGROUND: Cold- and heat-induced urticaria are chronic physical urticaria conditions in which wheals, angioedema or both are evoked by skin exposure to cold and heat respectively. The diagnostic work up of both conditions should include skin provocation tests and accurate determination of critical temperature thresholds (CTT) for producing symptoms in order to be able to predict the potential risk that each individual patient faces and how this may be ameliorated by therapy. OBJECTIVE: To develop and validate TempTest(®) 4, a simple and relatively inexpensive instrument for the accurate determination of CTT which may be used in clinical practice. METHODS: TempTest(®) 4 has a single 2 mm wide 350 mm U-shaped Peltier element generating a temperature gradient from 4 °C to 44 °C along its length. Using a clear plastic guide placed over the skin after provocation, CTT values may be determined with an accuracy of ±1 °C. Here, TempTest(®) 4 was compared with its much more expensive predecessor, TempTest(®) 3, in inducing wheals in 30 cold urticaria patients. RESULTS: Both TempTest(®) 4 and TempTest(®) 3 induced wheals in all 30 patients between 8 ° and 28 °C. There was a highly significant (P < 0.0001) correlation between the instruments in the CTT values in individual patients. CONCLUSION: The TempTest(®) 4 is a simple, easy to use, licensed, commercially available and affordable instrument for the determination of CTTs in both cold- and heat-induced urticaria.

Platelet-activating factor (PAF) induces wheal and flare skin reactions independent of mast cell degranulation.

BACKGROUND: Platelet-activating factor (PAF) causes wheal and flare responses which are abrogated by H1-antihistamines giving rise to the hypothesis that PAF-induced wheal development is secondary to histamine release from dermal mast cells. But is this hypothesis correct? METHODS: Wheal and flare responses were induced by intradermal injection of PAF, codeine and histamine in 14 healthy volunteers. Dermal histamine and PGD2 contractions were measured using microdialysis. RESULTS: PAF, unlike histamine and codeine, did not cause a statistically significant rise in mean histamine levels with ten persons showing negligible histamine release. Codeine caused a significant but variable histamine release, ranging from 29 to 282 ng/ml. Codeine, but not PAF or histamine, caused a small but statistically significant release of PGD2. CONCLUSION: Wheal and flare reactions in human skin induced by PAF are not associated with histamine release and, therefore, appear to be independent of mast cell degranulation.

[Chronic spontaneous urticaria: An autoimmune disease?]. / Chronische spontane Urtikaria: Eine Autoimmunerkrankung?

The identification of the causes of chronic spontaneous urticaria (CSU) is difficult. The recognition of functional autoantibodies against FcεRI and/or against IgE in some patients with CSU led to the concept of autoimmune etiology of the disease. Clinical and laboratory features in a subpopulation of CSU patients also point to an autoimmune etiology of the disease. This review will present and discuss the relevance of functional autoantibodies in CSU pathogenesis and their implications for treatment and prognosis.

Measurement of the oxidation state of mitochondrial cytochrome c from the neocortex of the mammalian brain.

Diffuse optical remission spectra from the mammalian neocortex at visible wavelengths contain spectral features originating from the mitochondria. A new algorithm is presented, based on analytically relating the first differential of the attenuation spectrum to the first differential of the chromophore spectra, that can separate and calculate the oxidation state of cytochrome c as well as the absolute concentration and saturation of hemoglobin. The algorithm is validated in phantoms and then tested on the neocortex of the rat during an anoxic challenge. Implementation of the algorithm will provide detailed information of mitochondrial oxygenation and mitochondrial function in physiological studies of the mammalian brain.