Evaluation of three methods for using the Duotip-Test device for skin testing.

The sensitivity and precision of rotation, prick and puncture methods of using the Duotip-Test for epicutaneous allergy skin testing were evaluated. Forty-one volunteers who had not taken any antihistamines within the previous two weeks were recruited. The mean age was 21.6 years (range 18 to 25 years). Histamine hydrochloride 1 mg/ml and 50% glycerol saline were used as positive and negative controls, respectively. Each method of testing was performed in triplicate on the volar surface of both forearms. Wheal and flare were measured 15 minutes later. Rotation, prick and puncture methods produced histamine mean wheal diameter +/- standard deviation of 6.61 +/- 0.87 mm, 3.86 +/- 1.03 mm, and 3.00 +/- 0.65 mm, respectively (p < 0.01). The coefficient of variation of rotation method was 13.13%. It was the only method that gave coefficient of variation lower than 20%. False negative and false positive proportions of rotation method using a 4 mm criterion for positive reaction were 1.5% and 0.75%, respectively. Rotation method was well accepted by the volunteers although it was ranked highest in pain. We concluded that the rotation method of using Duotip-Test is a highly reliable technique for skin testing.

Efecto inhibitorio del astemizol en pruebas cutáneas con histamina / The effect of the astemizol to inhibit the cutaneos response to the histamine

Objetivo. Determinar el efecto del astemizol para inhibir la respuesta cutánea a la histamina. Material y método. Se realizó un ensayo clínico en sujetos adultos sanos; se efectuaron pruebas cutáneas con histamina por prick (1 mg/ml) e intradérmicas (0.01 mg/ml) diarias, durante la toma de 10 mg de astemizol en ayunas en un periodo de siete días y otros tantos más después de suspenderlo, así como el día 14, 21, y 28. Se determinó la inhibición y la reaparición de la respuesta cutánea. Resultados. Se estudiaron 12 sujetos con edad promedio de 36 años ñ 11.2 DS. La inhibición completa se presentó a partir del cuarto día y la mayoría de los sujetos (79 por ciento) hasta el séptimo día. La reacción normal se recuperó en más de siete días pero menos de 14 en el 100 por ciento. Conclusiones. De acuerdo con estos resultados, el astemizol inhibe la reacción cutánea a la histamina desde el primer día en 50 por ciento de los sujetos y su mayor acción es al séptimo día, mientras que al suspenderlo la respuesta normal se recupera en más de siete días

Effects of ranitidine alone and in combination with chlorpheniramine on histamine-induced wheal and flare and psychomotor performance.

Some reports suggest that addition of an H2 antagonist increases the efficacy of H1 antagonist but the influence on the side effect profile of antihistamines are largely unknown. The effects of ranitidine, chlorpheniramine, their combination and placebo on histamine induced wheal and flare, psychomotor performance and subjective symptoms were studied in 6 healthy male volunteers in a double blind randomized and cross-over (Latin square) study. Ranitidine significantly reduced the histamine induced wheal at 4 hrs (P < 0.05). Chlorpheniramine and the combination significantly reduced both histamine induced wheal and flare at 2 hrs and at 4 hrs (P < 0.05). Addition of ranitidine reduced the feeling of sleepiness produced by chlorpheniramine, though other subjective symptoms were not affected. None of the treatment schedules produced any consistent change in the psychomotor performance of the volunteers.

Biological standardization of pollen allergens from India.

Standardization of allergens are achieved by in vitro and in vivo methods. Some of the allergens from Western countries are standardized using biological potency of the extracts but no attempt has been made till now to standardize any of the pollen extracts from India based on biological units. Therefore, we have attempted to standardize two important pollen allergens Ricinus communis and Holoptelea integrifolia by biological methods. Broadly the methods adopted by Dreborg and Grimmer (1983) was followed. Skin prick tests were carried out with the extracts of R. communis and H. integrifolia on 15 allergic patients in five three fold log dilutions starting with 1:10, in 50% glycerinated buffer. Glycerinated buffer (50%) and histamine dihydrochloride (1 mg/ml) were used as negative and positive controls, respectively. The mean wheal diameter obtained with different concentrations showed a gradual systematic fall with increase in dilution. The mean relative diameter (% of histamine reaction) varied from 124.1 +/- 8.9 to 33.7 +/- 6.1 and 78.9 +/- 5.5 to 21.4 +/- 3.8 with the highest and lowest concentrations of R. communis and H. integrifolia pollen antigens, respectively. The histamine equivalent concentration of antigen 1,000 Biological Units (BU) obtained for crude pollen extracts of R. communis and H. integrifolia was 1:17 and 1:22 respectively.