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Physiology & Behavior Oct 2023Humans produce odorous secretions from multiple body sites according to the microbiomic profile of each area and the types of secretory glands present. Because the... (Review)
Review
Humans produce odorous secretions from multiple body sites according to the microbiomic profile of each area and the types of secretory glands present. Because the axilla is an active, odor-producing region that mediates social communication via the sense of smell, this article focuses on the biological mechanisms underlying the creation of axillary odor, as well as the intrinsic and extrinsic factors likely to impact the odor and determine individual differences. The list of intrinsic factors discussed includes sex, age, ethnicity, emotions, and personality, and extrinsic factors include dietary choices, diseases, climate, and hygienic habits. In addition, we also draw attention to gaps in our understanding of each factor, including, for example, topical areas such as the effect of climate on body odor variation. Fundamental challenges and emerging research opportunities are further outlined in the discussion. Finally, we suggest guidelines and best practices based on the factors reviewed herein for preparatory protocols of sweat collection, data analysis, and interpretation.
Topics: Humans; Odorants; Sweat; Smell; Sweating; Axilla
PubMed: 37516230
DOI: 10.1016/j.physbeh.2023.114307 -
MedRxiv : the Preprint Server For... Oct 2023Olfactory impairment is common in older adults and may be associated with adverse cardiovascular health; however, empirical evidence is sparse.
BACKGROUND
Olfactory impairment is common in older adults and may be associated with adverse cardiovascular health; however, empirical evidence is sparse.
OBJECTIVE
To examine olfaction and the risk of coronary heart disease (CHD), stroke, and congestive heart failure (CHF).
METHODS
This study included 2,537 older adults (aged 75.6±2.8 years) from the Health ABC Study with olfaction assessed by the 12-item Brief Smell Identification Test in 1999-2000, defined as poor (score ≤8), moderate (9-10), or good (11-12). The outcomes were incident CHD, stroke, and CHF.
RESULTS
During up to 12-year follow-up, 353 incident CHD, 258 stroke, and 477 CHF events were identified. Olfaction was associated with incident CHF, but not with CHD or stroke. After adjusting for demographics, the cause-specific hazard ratio (HR) of CHF was 1.35 (95% confidence interval (CI): 1.08, 1.70) for moderate and 1.39 (95%CI: 1.09, 1.76) for poor olfaction. With additional adjustment for lifestyle, chronic diseases, and biomarkers of CHF, the HR was modestly attenuated to 1.32 (95%CI: 1.05, 1.66) for moderate and 1.28 (95%CI: 1.01, 1.64) for poor olfaction. These associations were robust in pre-planned subgroup analyses by age, sex, race, and prevalent CHD/stroke. However, the associations appeared to be evident among participants who reported very-good-to-excellent health (HR=1.47 (95%CI: 1.02, 2.13) for moderate and 1.76, (95%CI: 1.20, 2.57) for poor olfaction). In contrast, null association with CHF was found among those with fair-to-poor self-reported health.
CONCLUSIONS
In community-dwelling older adults, a single olfaction test was associated with a long-term risk for incident CHF, particularly among those reporting very-good-to-excellent health.
PubMed: 37961698
DOI: 10.1101/2023.10.27.23297697 -
International Archives of... Jul 2023Primary ciliary dyskinesia (PCD) is a rare inherited disease associated with impairment of mucociliary transport and, consequently, with a high incidence of chronic...
Primary ciliary dyskinesia (PCD) is a rare inherited disease associated with impairment of mucociliary transport and, consequently, with a high incidence of chronic rhinosinusitis. For patients with chronic rhinosinusitis who remain symptomatic despite medical treatment, endoscopic sinus surgery is a safe and effective therapeutic option. However, to date, no studies have been found evaluating the effect of surgery on the quality of life associated with the effect on olfaction and nasal endoscopy findings of patients with primary ciliary dyskinesia and chronic rhinosinusitis. To describe the effect of endoscopic sinus surgery on the quality of life, on olfaction, and on nasal endoscopy findings of adults with PCD and chronic rhinosinusitis. Four patients who underwent endoscopic sinus surgery were included. The Sinonasal Outcome Test-22 (SNOT-22) score, the Nasal Obstruction Symptom Evaluation (NOSE) questionnaire, and the Lund-Kennedy score were collected preoperatively and at 3 and 6 months postoperatively. The olfaction as assessed with the University of Pennsylvania Smell Identification Test (UPSIT), which was administered preoperatively and 3 months postoperatively. A total of 4 patients with a mean age of 39.3 years old (3 men and 1 woman) completed the study. All patients showed clinically significant improvement in the SNOT-22, NOSE, and Lund-Kennedy scores at 3 months postoperatively, and this improvement was sustained throughout the follow-up period. However, olfaction did not improve after surgery. The endoscopic sinus surgery treatment of chronic rhinosinusitis in adults with PCD was associated with improvement in quality of life and endoscopic findings. However, no improvement in olfaction was demonstrated. Studies with a larger number of patients and control groups should help confirm these findings.
PubMed: 37564476
DOI: 10.1055/s-0042-1746193 -
Empirical Software Engineering 2024Test smells are symptoms of sub-optimal design choices adopted when developing test cases. Previous studies have proved their harmfulness for test code maintainability...
Test smells are symptoms of sub-optimal design choices adopted when developing test cases. Previous studies have proved their harmfulness for test code maintainability and effectiveness. Therefore, researchers have been proposing automated, heuristic-based techniques to detect them. However, the performance of these detectors is still limited and dependent on tunable thresholds. We design and experiment with a novel test smell detection approach based on machine learning to detect four test smells. First, we develop the largest dataset of manually-validated test smells to enable experimentation. Afterward, we train six machine learners and assess their capabilities in within- and cross-project scenarios. Finally, we compare the ML-based approach with state-of-the-art heuristic-based techniques. The key findings of the study report a negative result. The performance of the machine learning-based detector is significantly better than heuristic-based techniques, but none of the learners able to overcome an average F-Measure of 51%. We further elaborate and discuss the reasons behind this negative result through a qualitative investigation into the current issues and challenges that prevent the appropriate detection of test smells, which allowed us to catalog the next steps that the research community may pursue to improve test smell detection techniques.
PubMed: 38456065
DOI: 10.1007/s10664-023-10436-2 -
Acta Neuropathologica Communications May 2024The majority of patients with Parkinson disease (PD) experience a loss in their sense of smell and accumulate insoluble α-synuclein aggregates in their olfactory bulbs...
The majority of patients with Parkinson disease (PD) experience a loss in their sense of smell and accumulate insoluble α-synuclein aggregates in their olfactory bulbs (OB). Subjects affected by a SARS-CoV-2-linked illness (COVID-19) also frequently experience hyposmia. We previously postulated that microglial activation as well as α-synuclein and tau misprocessing can occur during host responses following microbial encounters. Using semiquantitative measurements of immunohistochemical signals, we examined OB and olfactory tract specimens collected serially at autopsies between 2020 and 2023. Deceased subjects comprised 50 adults, which included COVID19 + patients (n = 22), individuals with Lewy body disease (e.g., PD; dementia with Lewy bodies (n = 6)), Alzheimer disease (AD; n = 3), and other neurodegenerative disorders (e.g., progressive supranuclear palsy (n = 2); multisystem atrophy (n = 1)). Further, we included neurologically healthy controls (n = 9), and added subjects with an inflammation-rich brain disorder as neurological controls (NCO; n = 7). When probing for microglial and histiocytic reactivity in the anterior olfactory nuclei (AON) by anti-CD68 immunostaining, scores were consistently elevated in NCO and AD cases. In contrast, microglial signals on average were not significantly altered in COVID19 + patients relative to healthy controls, although anti-CD68 reactivity in their OB and tracts declined with progression in age. Mild-to-moderate increases in phospho-α-synuclein and phospho-tau signals were detected in the AON of tauopathy- and synucleinopathy-afflicted brains, respectively, consistent with mixed pathology, as described by others. Lastly, when both sides were available for comparison in our case series, we saw no asymmetry in the degree of pathology of the left versus right OB and tracts. We concluded from our autopsy series that after a fatal course of COVID-19, microscopic changes in the rostral, intracranial portion of the olfactory circuitry -when present- reflected neurodegenerative processes seen elsewhere in the brain. In general, microglial reactivity correlated best with the degree of Alzheimer's-linked tauopathy and declined with progression of age in COVID19 + patients.
Topics: Humans; COVID-19; Olfactory Bulb; Aged; Male; Female; Aged, 80 and over; Middle Aged; Microglia; alpha-Synuclein; tau Proteins; SARS-CoV-2; Neurodegenerative Diseases
PubMed: 38698465
DOI: 10.1186/s40478-024-01761-8 -
Current Opinion in Insect Science Oct 2023Extracting spatial information from temporal stimulus patterns is essential for sensory perception (e.g. visual motion direction detection or concurrent sound... (Review)
Review
Extracting spatial information from temporal stimulus patterns is essential for sensory perception (e.g. visual motion direction detection or concurrent sound segregation), but this process remains understudied in olfaction. Animals rely on olfaction to locate resources and dangers. In open environments, where odors are dispersed by turbulent wind, detection of wind direction seems crucial for odor source localization. However, recent studies showed that insects can extract spatial information from the odor stimulus itself, independently from sensing wind direction. This remarkable ability is achieved by detecting the fine-scale temporal pattern of odor encounters, which contains information about the location and size of an odor source, and the distance between different odor sources.
Topics: Animals; Odorants; Insecta; Smell; Wind
PubMed: 37419251
DOI: 10.1016/j.cois.2023.101082 -
Alternative Therapies in Health and... Sep 2023The phenomena of olfactory and gustatory dysfunction disorders (OGD) are hardly unique to COVID-19. However, the widespread incidence of OGD as sequelae of COVID-19 has... (Review)
Review
CONTEXT
The phenomena of olfactory and gustatory dysfunction disorders (OGD) are hardly unique to COVID-19. However, the widespread incidence of OGD as sequelae of COVID-19 has provoked rejuvenated interest in these long existing, but poorly studied maladies.
OBJECTIVE
This second of a three-part review discusses past and current approaches for treatment of OGD, not restricted to those that COVID-19 has caused, with the intention to lay a foundation for consideration of new paradigms for evaluation and management of OGD.
DESIGN
The researcher performed a narrative review by searching databases including PubMed, Sciencedirect, Google Scholar, Old Dominion University Libraries, and the websites of various medical journals. Searches included numerous combinations of keywords accompanied by the phrases, loss of sense of smell and taste, olfactory and gustatory dysfunction disorders, as well as the terms anosmia, parosmia, ageusia, and parageusia. Such keywords included viruses, bacteria, fungi, protozoa, parasites, infection, COVID-19, treatments, medications, steroids, supplements, nutrients, alternative medicine, acupuncture, olfactory training, clinical trials, cranial nerves, pathogenesis, pathophysiology, and etiology.
SETTING
The Liebell Clinic, Virginia Beach, VA, USA.
CONCLUSIONS
The epidemiology and hypotheses of pathophysiology of post-COVID OGD has been addressed via numerous studies and reviews. However, extremely limited evidence of effective treatment for chronic OGD, in general, exists, Global demand for any treatment capable of reducing or resolving it is unprecedented. Past and present treatment approaches and recently initiated clinical trials, since the onset of the pandemic, have yet to yield any significant results.
Topics: Humans; COVID-19; Smell; SARS-CoV-2; Taste Disorders; Olfaction Disorders
PubMed: 37574205
DOI: No ID Found -
Animals : An Open Access Journal From... Oct 2023Horses constantly face several challenges inherent to the domestic environment, and it is common for the expression of their natural behavior to be drastically limited.... (Review)
Review
Horses constantly face several challenges inherent to the domestic environment, and it is common for the expression of their natural behavior to be drastically limited. Environmental enrichment has been suggested as an alternative to improve the captive situation of domestic horses. Among the recently proposed enrichment strategies, olfactory stimulation has emerged as a method for improving several aspects related to animal behavior. Olfaction is a sensory modality that plays a significant role in the expression of equine behavior, and in recent years, studies have shown that olfactory stimulation can influence the physiological and behavioral parameters of horses. This review provides current information on the anatomical particularities of the equine olfactory system, presents the physiological mechanisms involved in the odor detection process, and demonstrates how stress can interfere with this process. Finally, the use of olfactory stimulation as an environmental enrichment for domestic horses () is explored. The need for new studies that answer pertinent questions related to this topic is discussed throughout the manuscript.
PubMed: 37893904
DOI: 10.3390/ani13203180 -
PloS One 2024While measures to detect psychophysical olfactory ability are a crucial part of clinicians' assessment of potential olfactory loss, it gives no indication of how...
While measures to detect psychophysical olfactory ability are a crucial part of clinicians' assessment of potential olfactory loss, it gives no indication of how olfaction is experienced by the patient and these different aspects often deviate substantially. To ensure quality and reproducibility of subjectively reported olfactory experience and significance, the Importance of Olfaction Questionnaire (IO-Q) was introduced around a decade ago, and while initial validations have produced promising results, important aspects remain nearly unexamined. For example, the test-retest reliability has rarely been examined and the difference of online versus pen-and-paper administration remains unexplored. Here, we translated IO-Q to Danish and examined its validity, test-retest reliability and mode of administration. A cohort of 179 younger, Danish participants with a high level of English proficiency took the test twice with varying time in-between. The first test was taken digitally and in English, while the second was taken using pen-and-paper and in Danish. The distribution of scores and the relationship between the IO-Q and subscale scores were nearly identical between tests, indicating little to no influence of language/test modality in the sampled population. The internal consistency was comparable to previously published results. Likewise, an acceptable test-retest reliability was observed for the full IO-Q and slightly lower for subscales. No significant effect of time was found across several weeks. In conclusion, the IO-Q performed satisfactorily in all examinations and could therefore serve as a valuable clinical measure of subjective olfactory experience, and its Danish translation shows highly similar characteristics to the original, English version.
Topics: Humans; Smell; Reproducibility of Results; Surveys and Questionnaires; Physical Examination; Denmark; Psychometrics; Quality of Life
PubMed: 38241356
DOI: 10.1371/journal.pone.0269211 -
Frontiers in Allergy 2024Since the advent of the Universal Detector Calibrant (UDC) by scientists at Florida International University in 2013, this tool has gone largely unrecognized and... (Review)
Review
Since the advent of the Universal Detector Calibrant (UDC) by scientists at Florida International University in 2013, this tool has gone largely unrecognized and under-utilized by canine scent detection practitioners. The UDC is a chemical that enables reliability testing of biological and instrumental detectors. Training a biological detector, such as a scent detection canine, to respond to a safe, non-target, and uncommon compound has significant advantages. For example, if used prior to a search, the UDC provides the handler with the ability to confirm the detection dog is ready to work without placing target odor on site (i.e., a positive control), thereby increasing handler confidence in their canine and providing documentation of credibility that can withstand legal scrutiny. This review describes the UDC, summarizes its role in canine detection science, and addresses applications for UDC within scent detection canine development, training, and testing.
PubMed: 38533355
DOI: 10.3389/falgy.2024.1366596