Dangerous liaison: sexually transmitted allergic reaction to Brazil nuts.

Brazil nuts are the second most frequent cause of nut allergy in the United Kingdom. We report the case of a 20-year-old woman with documented Brazil nut allergy who developed widespread urticaria and mild dyspnea after intercourse with her boyfriend who had earlier consumed Brazil nuts. Skin prick testing with the boyfriend's semen after Brazil nut consumption confirmed significant reactivity whereas a sample before nut consumption was negative. We believe this to be the first case of a sexually transmitted allergic reaction.     

Do ethnicity and gender have an impact on pain thresholds in minor dermatologic procedures?

Background and Objectives: The perception of pain is a personal experience influenced by many factors, including genetic, ethnic and cultural issues. Understanding these perceptions is especially important in dermatologic patients undergoing minor surgical operations and who often differ in their pain response to surgical treatments. Little is known about how these differences affect the perception of experimental pain. The purpose of this study was to determine experimental pain perception differences in three distinct East Asian ethnic populations.
Methods: Pain thresholds were examined with a psychophysical computerized quantitative thermal sensory testing device (TSA 2001) in healthy volunteers recruited from three different Asian ethnic groups. Using the methods of limits, experimental pain perception threshold was measured on the forehead and volar aspect of the forearm in 49 healthy subjects. The measurements were then repeated after skin barrier perturbation with adhesive tape stripping of the stratum corneum. All three ethnic groups were analyzed separately with respect to age, gender educational level and skin type.
Results: A total of 20 Chinese, 14 Malay and 15 Indian subjects completed the study. Thermal pain thresholds were similar in all three ethnic groups before and after tape strippings. No significant differences were noted between genders.
Conclusions: Using quantitative sensory thermal testing, we demonstrated that no significant differences in pain occur between different races and genders.     

The effects of occipital ablation on a conditioned visual avoidance learning task in young and old rats

Previous data indicate that learning of a conditioned visual avoidance task following simultaneous complete bilateral occipital ablations is affected by the age of the organism as well as the postoperative recovery period. The present study investigated the performance of the avoidance task, following complete occipital ablations, in young and older rats given two different recovery intervals. Young rats given 10 days to recover performed more poorly than the young control animals; given 20 days to recover, young rats performed comparable to controls. Older rats given 10 days to recover performed significantly better than the controls; given 20 days to recover, older rats did not show a decrease in performance. The present finding is consistent with previous data which show that the occipital cortex exerted an inhibitory effect on the learning ability of the avoidance task in older rats, which, upon removal, enhanced the performance of these rats on the task.     

Noradrenergic projections to brainstem nuclei: evidence for differential projections from noradrenergic subgroups

Retrograde transport of the fluorescent tracer True Blue was used in combination with immunohistochemical staining of dopamine-beta-hydroxylase (a marker protein for noradrenergic neurons) to determine the origin of noradrenergic projections to three cranial nerve nuclei: 1) the motor nucleus of the trigeminal nerve, 2) the motor nucleus of the facial nerve, and 3) the spinal trigeminal nucleus pars interpolaris. Noradrenergic cells in the rat brainstem were divided into subgroups and their numbers were determined in serial sections stained with an antiserum to rat dopamine-beta-hydroxylase. Following tracer injections into the three brainstem nuclei, retrogradely labeled noradrenergic neurons were counted and the percentage of True Blue-labeled noradrenergic cells in each subgroup was calculated. Injections of tracer into the three cranial nerve nuclei resulted in distinctly different labeling patterns of noradrenergic cells. Of the total number of norepinephrine neurons projecting to the motor nucleus of the trigeminal nerve, 68% were observed within the A7 cell group; 75% of those innervating the motor nucleus of the facial nerve were found in the A5 cell group, and 65% of those projecting to the spinal trigeminal nucleus pars interpolaris were present in the locus ceruleus and subceruleus. These findings indicate that norepinephrine cells in the rat brainstem do not constitute a homogeneous population of cells but that several discrete systems can be identified that differ not only in topography but also in the terminal distribution of their axons. This combined retrograde transport-immunohistochemical study reveals a much higher degree of topographic order in the projections of norepinephrine neurons than has previously been recognized. The observation of differential projections of noradrenergic subgroups argues against the notion of a global influence of these cells over functionally diverse areas of the brainstem.