Hedonic perception of odors in children aged 5-8 years is similar across 18 countries: Preliminary data.

OBJECTIVE: Olfactory preference emerges very early in life, and the sense of smell in children rapidly develops until the second decade of life. It is still unclear whether hedonic perception of odors is shared in children inhabiting different regions of the globe. METHODS: Five-hundred ten healthy children (N = 510; ngirls = 256; nboys = 254) aged from 5 to 8 years from 18 countries rated the pleasantness of 17 odors. RESULTS: The hedonic perception of odors in children aged between 5 and 8 years was rather consistent across 18 countries and mainly driven by the qualities of an odor and the overall ability of children to label odorants. CONCLUSION: Conclusions from this study, being a secondary analysis, are limited to the presented set of odors that were initially selected for the development of U-Sniff test and present null findings for the cross-cultural variability in hedonic perception of odors across 18 countries. These two major issues should be addressed in the future to either contradict or replicate the results presented herewith. This research lays fundament for posing further research questions about the developmental aspects of hedonic perception of odors and opens a new door for investigating cross-cultural differences in chemosensory perception of children.

Proposal for a standardised method for the identification of essential oils by HPTLC.

The European Pharmacopoeia (Ph. Eur.), includes both individual monographs on essential oils and a general monograph that covers all essential oils for pharmaceutical use, whether covered by an individual monograph or not. The individual monographs generally describe gas chromatography as a first identification test, while thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC) methods are included in the second identification series. To comply with Ph. Eur. general chapter 2.8.25. High-performance thin-layer chromatography of herbal drugs and herbal drug preparations, HPTLC parameters must be standardised. Currently, 18 of the 32 monographs on essential oils feature the same TLC/HPTLC method, but differ in terms of the other conditions described. A single, standardised chromatographic system with a system suitability test (SST) and intensity markers for all 32 essential oils covered by individual monographs would be desirable, particularly for pharmacies and other users that cannot perform gas chromatography for financial reasons. To this end, this paper describes the development of a general HPTLC method for the identification of essential oils in compliance with general chapter 2.8.25. The method proposes the use of ethyl acetate, toluene (5:95 V/V) as mobile phase, isoeugenol/isoeugenyl acetate for the SST, and a combination of one alcohol (either borneol or linalool) and one ester (either linalyl acetate or bornyl acetate) as intensity markers.

Exposure to odours improves olfactory function in healthy children.

BACKGROUND: Short-term exposure to odours, also called "olfactory training" has been shown to improve olfactory function in healthy people but also in people with olfactory loss. Aim of this single center, prospective, controlled study was to investigate the change of olfactory function following twice-daily, short-term exposure to 4 odours over a period of approximately 12 weeks. MATERIAL AND METHODS: We compared odour identification abilities and odour thresholds between an olfactory training group (TR group) and a group that did not perform such training (noTR group). Participants exposed themselves twice daily to 4 odours ("rose", "eucalyptus", "lemon", "clove"). Olfactory testing was performed before and after the training period using the "Sniffin' Sticks" test kit (odour identification plus odour thresholds). RESULTS: At baseline the two groups were not significantly different in terms of age and measures of olfactory sensitivity. The TR group performed significantly better for odour thresholds for all 4 odours compared to the noTR group after 12 weeks of olfactory training. Also, with regard to odour identification the TR group outperformed the noTR group. No significant differences were found for diary-based intensity ratings. CONCLUSION: Repeated exposure to odours seems to improve general olfactory sensitivity in children.

Olfactory speed - Temporal odor processing of paired stimuli.

OBJECTIVES: Compared to other senses, temporal perception of odors seems fairly slow. In addition it has been shown in previous studies that even not consciously perceived odors could influence our behavior. Aim of the current study therefore was to study the interstimulus interval (ISI) length, which is necessary between two repetitive stimuli to be able to perceive them separately. The additional aim focused on observing central odor processing of not perceived odorous stimuli. MATERIALS AND METHODS: The study was divided into three parts. In each part healthy, normosmic volunteers were included. In part I and II stimulus pairs (CO2, H2S, orange and phenyl ethyl alcohol (PEA)) were presented to the subjects via a computer-controlled olfactometer with short ISI of 0.6-9s. The decision whether one or two stimuli were perceived was recorded. In addition the influence of odor valence, trigeminallity and concentrations was observed. In part III olfactory event-related potentials (OERPs) to perceived and not-perceived odors were recorded. RESULTS: The two stimuli of a stimulus pair were perceived separately more often with increasing ISI length. This increase was significant until an ISI between the stimuli of 4s. Odor intensity, pleasantness, trigeminallity and sex had no major influence on this. In addition we were able to observe that OERPs are less often detected in response to not perceived olfactory stimuli. However, the presence of OERP in response to not perceived stimuli in more than half of the cases indicated that even not perceived stimuli are centrally processed.

Injury type-specific calcium channel alpha 2 delta-1 subunit up-regulation in rat neuropathic pain models correlates with antiallodynic effects of gabapentin.

The calcium channel alpha2delta-1 subunit is a structural subunit important for functional calcium channel assembly. In vitro studies have shown that this subunit is the binding site for gabapentin, an anticonvulsant that exerts antihyperalgesic effects by unknown mechanisms. Increased expression of this subunit in the spinal cord and dorsal root ganglia (DRG) has been suggested to play a role in enhanced nociceptive responses of spinal nerve-injured rats to innocuous mechanical stimulation (allodynia). To investigate whether a common mechanism underlies allodynic states derived from different etiologies, and if so, whether similar alpha2delta-1 subunit up-regulation correlates with these allodynic states, we compared DRG and spinal cord alpha2delta-1 subunit levels and gabapentin sensitivity in allodynic rats with mechanical nerve injuries (sciatic nerve chronic constriction injury, spinal nerve transection, or ligation), a metabolic disorder (diabetes), or chemical neuropathy (vincristine neurotoxicity). Our data indicated that even though allodynia occurred in all types of nerve injury investigated, DRG and/or spinal cord alpha2delta-1 subunit up-regulation and gabapentin sensitivity only coexisted in the mechanical and diabetic neuropathies. Thus, induction of the alpha2delta-1 subunit in the DRG and spinal cord is likely regulated by factors that are specific for individual neuropathies and may contribute to gabapentin-sensitive allodynia. However, the calcium channel alpha2delta-1 subunit is not the sole molecular change that uniformly characterizes the neuropathic pain states.