Acoustic reflections have been used in adult humans to determine nasal cavity dimensions in terms of cross-sectional areas as a function of the distance from the nostril (J. Appl. Physiol., 66:295–303, 1989). In order to measure nasal cavity dimensions in guinea pigs, we modified equipment for use in humans by decreasing sound tube dimensions, increasing sampling frequency, and applying a special nosepiece. We measured 5 guinea pigs (Duncan Hartley strain, 500 g) on two days, before and after instillation of epinephrine and histamine in one nostril. In the control measurements, the minimum cross-sectional area of a nasal cavity was 1.1 mm2 (SD = 0.3 mm2), and the volume from the nostril to 20 mm into the nasal cavity was 60 mm3 (SD = 19 mm3). There was a tendency (P < 0.10) for epinephrine to increase minimum cross-sectional area on the treated side and volumes on both sides. Histamine decreased volume on both sides (P < 0.05), but not uniformly between animals. Measurements in a tube with 2 mm internal diameter (area 3.1 mm2) underestimated true area by approximately 30%. The method, therefore, at its present state of development, measures changes in dimensions rather than absolute values. It is concluded that the acoustic reflections technique may be a useful alternative to other, more invasive methods to assess nasal cavity dimensions in guinea pigs, but further studies are necessary to improve and validate the method.

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The effects of antigen and histamine on the changes of nasal passage patency in 112 guinea pigs with or without allergic rhinitis were evaluated by acoustic rhinometry. The percent change of volume from the nostril to 2 cm into the nasal cavity showed significant reduction of 31.10 +/- 4.11% at 10 minutes and 31.10 +/- 4.11% at 30 minutes after antigen challenge in sensitized guinea pigs. The pretreatment with ketotifen, an H1-histamine receptor antagonist as well as mast cell stabilizing drug, blocked dose-dependently the effects of antigen on those changes in volume. Furthermore, instillation of 10(4) micrograms/mL histamine reduced significantly nasal passage patency to 33.77 +/- 4.63% at 10 minutes and 42.76 +/- 3.32% at 30 minutes after challenge compared with that before challenge and ketotifen inhibited the effects of histamine, which indicated that histamine is an important mediator of allergic upper airway responses in guinea pigs. These results show that acoustic rhinometry is a useful technique to assess the nasal blockade in allergic guinea pigs.

Many publications have repeatedly indicated that there seems to be a correlation between neoplastic disease and certain types of psychological situations.