Hair Samples Research Articles

Studies on the Assessment of Hair Cortisol Concentration in Dogs by Radioimmunoassay (RIA)

Background: Hair cortisol Concentration (HCC) is often used as a measure of chronic stress responses in humans. The use of Radioimmunoassay (RIA) and HCC to assess stress in hospitalized dogs has been poorly reported in the literature in India and Central East Asia. This paper presents a modified protocol for measuring HCC in dog hair samples for stress assessment using RIA. Methods: Estimation of HCC concentrations of healthy (n=20) and hospitalized (n=20) dogs was done using RIA. Hair samples were collected from a dog’s nape region and weighed to measure HCC concentration. The study used RIA-enabled dissevered spiking and detectable concentration-based modifications to measure HCC. Five known cortisol concentration standards (viz 19.0 nmol/l, 47.9 nmol/l, 190 nmol/l, 238.66 nmol/l and 713.33 nmol/l) were used, with the first three readily available with a cortisol RIA kit. The samples were spiked with 50 µL of the standard and analysed in a gamma counter to take counts per minute (CPM). The final concentration of HCC was estimated in nmol/l and derived in pg/mg as per standard methods. Result: Healthy dogs had a mean HCC of 6.24±0.84 pg/mg, while hospitalized dogs had 31.65±5.87 pg/mg. A significant deviation was observed in both groups. A box and whisker graph showed an HCC range of 0.36 to 13.78 pg/mg for healthy dogs and 8.70 to 65.25 pg/mg for hospitalized dogs. The interquartile range (25th to 75th percentile) was 3.55 to 9.24 pg/mg for healthy dogs and 14.43 to 46.22 for hospitalized dogs. The observed median for healthy dogs was 6.16 pg/mg and 22.62 pg/mg for hospitalized dogs. The study shows higher HCC in hospitalized sick dogs compared to clinically healthy ones, suggesting hair sample collection as a simple stress assessment method and RIA as a promising HCC detection technique.

Advancements in liquid chromatography‐mass spectrometry for amphetamine analysis in unconventional biological matrices: Focus on oral fluid and hair samples

AbstractAmphetamines (AMPHs) and their derivatives are potent central nervous system stimulants, in 2020 an astonishing 34 million regular users were reported worldwide. Consequently, there has been a critical need for the development of methods capable of detecting these compounds in alternative biological matrices. The review article discusses the analysis of amphetamines and their derivatives in alternative biological matrices, such as hair and oral fluid (OF), using liquid chromatography‐mass spectrometry. Compiles data from 28 articles published between 2012 and 2022, focusing on 13 articles on OFs and 15 on hair analysis. The article highlights the advantages of using these alternative matrices, including less invasive collection methods, greater sample stability, and simplified extraction processes. Additionally, prevalent analytical practices such as the use of C18 columns and the incorporation of formic acid and methanol into mobile phases are discussed. Furthermore, it demonstrates that the most used method for collecting OF is the Quantisal device, as well as solid phase extraction is also the most used for the same matrix. The review serves as a guide for researchers interested in analytical methods for identifying AMPHs, offering insights into advances, challenges, and the most used in the area.

Prevalence of Psychoactive Substance Use During Pregnancy in Argentine Women: A Pilot Study Testing Maternal Hair

Background: The use of psychoactive substances (PSs) during pregnancy is a major public health concern because of their increasing prevalence worldwide. This study examined the understudied issue of gestational PS consumption in a cohort of Argentine delivering mothers. Methods: A cross-sectional pilot study involving 51 women receiving delivery care was conducted at the Santa Rosa Hospital in La Pampa, Argentina. Information on maternal sociodemographic characteristics, pregnancy history, and drug use was obtained through standardized interviews. Maternal hair samples were analyzed for alcohol, tobacco, licit, illicit, and prescription substance biomarkers using ultra-high-performance liquid chromatography high-resolution mass spectrometry and gas chromatography mass spectrometry. Results: During pregnancy, 49.0% of participants reported alcohol consumption, 25.5% reported tobacco use, and 23.5% reported cannabis use. Hair samples from 56.9% of the women were positive for illicit PSs, with the most frequent being cocaine (41.2%) and cannabis (15.7%). Among the women, 47.1% consumed alcohol during pregnancy. Of the 24 women with hair ethyl glucuronide ≥5 pg/mg, 33.3% drank until the end of gestation and 58.3% started a social drinking habit in the second half. The analysis also detected prescription substances (anticonvulsants, antidepressants, methadone, opioids, antihistamines, antiemetics, and analgesics), caffeine (70.6%), lidocaine, and levamisole, some of which were cocaine or opioid adulterants. Conclusions: This is the first study to objectively assess the consumption of licit and illicit PSs during pregnancy in Argentina. In contrast to most nearby countries, cocaine was the most detected illicit PS in this cohort of Argentine delivering women. This finding highlights the importance of regular monitoring of local trends in PS use during pregnancy.

Advances in SARMs anti-doping analysis.

Selective androgen receptor modulators (SARMs) are performance-enhancing drugs (PEDs) that stimulate anabolism, increase muscle mass and strength and promote recovery from exercise. The use of SARMs in sports is considered doping and is strictly prohibited by the World Anti-Doping Agency (WADA) and the International Federation of Horseracing Authorities (IFHA). To monitor the abuse of SARMs in sports, it is essential to develop advanced, selective and sensitive analytical methods that provide reliable results. This review evaluates the advances in this area, with a focus on the identification of target analytes related to SARMs, such as SARMs, their metabolites or markers. The aim is to identify targets that could extend the detection windows of SARMs, provide scientific support for results management and/or offer an indirect biomarker-based approach to doping control. This review also aims to evaluate the current liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods developed for the monitoring of SARMs in different biological matrices, including traditional matrices such as urine and serum/plasma samples, as well as alternative matrices such as dried blood spots, hair and nail samples.

Mechanical properties and low-velocity impact analysis of camel hair and hybrid camel hair/flax fibre-reinforced epoxy

Mechanical properties and low-velocity impact analysis of camel hair and hybrid camel hair/flax fibre-reinforced epoxy

Drug concentrations in hair and dried blood spots as PrEP adherence metrics during pregnancy and postpartum.

We evaluated hair tenofovir (TFV) concentrations as an adherence metric for HIV pre-exposure prophylaxis (PrEP) during pregnancy and postpartum and compared hair levels with tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS). Overall, 152 hair samples from 102 women and 36 hair-DBS paired samples from 29 women were collected from a subset of women in a cluster randomized trial. Having a partner known to be living with HIV was associated with higher hair TFV levels (p<0.001). Hair TFV concentrations were strongly correlated with DBS TFV-DP levels (r=0.76, p<0.001), indicating hair as promising cumulative adherence metric for perinatal PrEP assessment.

A methodological exploration of distinguishing hair quality based on hair proteomics

Hair is an advantageous biological sample due to its recordable, collectable, and storable nature. Hair's primary components are keratin and keratin-associated proteins. Owing to its abundance of cystine, keratin possesses impressive mechanical strength and chemical stability, formed by creating disulfide bonds as crosslinks within the protein peptide chain. Furthermore, keratin is cross-linked with keratin-associated proteins to create a complex network structure that provides the hair with strength and rigidity. Protein extraction serves as the foundation for hair analysis research. Bleaching hair causes damage to the structure between keratin and keratin-associated proteins, resulting in texture issues and hair breakage. This article outlines various physical treatment methods and lysate analysis that enhance the efficiency of hair protein extraction. The PLEE method achieves a three-fold increase in hair protein extraction efficiency when using a lysis solution containing SDS and combining high temperatures with intense shaking, compared to previous methods found in literature. We utilized the PLEE method to extract hair from both normal and damaged groups. Normal samples identified 156–157 proteins, including 51 keratin and keratin-associated proteins. The damaged group consisted of 155–158 identified proteins, of which 48–50 were keratin and keratin-associated proteins. Bleaching did not cause any notable difference in the protein identification of hair. However, it did reduce coverage of keratin and keratin-associated proteins significantly. Our hair protein extraction method provides extensive coverage of the hair proteome. Our findings indicate that bleaching damage results in subpar hair quality due to reduced coverage of protein primary sequences in keratin and keratin-associated proteins.

Monitoring of environmental persistent organic pollutants in hair samples of cats and dogs

This study investigated 32 persistent organic pollutants, including 9 organochlorine pesticides, 15 polychlorinated biphenyls, 6 polycyclic aromatic hydrocarbons, and 2 organophosphate pesticides in the hair samples of domestic cats and dogs living in an urban area in Samsun, Turkiye. Hair samples were collected from 35 cats and 38 dogs, grouped by sex and age (<3 or >3 years old). Samples were extracted using a liquid-liquid extraction method and analyzed by Gas Chromatography-Mass Spectrometry (GC–MS). The results revealed the presence of organochlorine pesticides (n = 58, 468.65 ± 92.30 ng/g), polycyclic aromatic hydrocarbons (n = 57, 15.65 ± 3.91 ng/g), polychlorinated biphenyls (n = 55, 54.11 ± 9.47 ng/g), and organophosphate pesticides (n = 25, 568.43 ± 113.17 ng/g) in the samples. PCBs 81, 118, 128, 208, and 2,4-DDE were not detected in any samples. Only one sample did not contain any of the searched compounds. Fluorene was the most frequently detected pollutant (n = 53, 72.6 %), followed by β-hexachlorocyclohexane (n = 34, 46.6 %). The highest maximum concentration was observed for hexachlorobenzene (2748.03 ng/g), followed by aldrin (2313.45 ng/g) and fenitrothion (2081.13 ng/g). Pollutant concentrations did not differ between cats and dogs, sexes, and ages (p > 0.05). This study highlights the significant threat that urban areas pose to pets, and therefore, POPs should be monitored periodically in hair and other samples. To the best of our knowledge, this is the first report to investigate POP levels in hair samples from cats and dogs in Turkiye.

Mothers in stress: hair cortisol of mothers living in marginalised Roma communities and the role of socioeconomic disadvantage

Roma living in marginalised communities are among the most disadvantaged groups in Slovakia. Socioeconomic disadvantage is associated with higher hair cortisol concentrations (HCC), including in parents. The aim of this study is therefore to assess differences in HCC, reflecting the levels of stress, between mothers living in MRCs and from the majority population, to assess the association of socioeconomic disadvantage with HCC, and whether disadvantage mediates the MRC/majority differences in HCC. Participants were mothers of children aged 15–18 months old living in MRCs (N=61) and from the Slovak majority population (N=90). During preventive paediatric visits, visits at community centres and home visits, hair samples and data by questionnaire were collected. HCC differed significantly between mothers living in MRCs and mothers from the majority population, with the mean HCC value being twice as high in mothers living in MRCs (22.98 (95% confidence interval, CI, 15.70–30.30) vs. 11.76 (8.34–15.20), p<0.05). HCC was significantly associated with education, household equipment and household overcrowding, but not with billing, socioeconomic stress and social support. The difference in HCC between mothers living in MRCs and mothers from the majority population was partially mediated by poor house equipment, such as no access to running water, no flushing toilet or no bathroom (the indirect effect of B=7.63 (95% CI: 2.12–13.92)). Practitioners and policymakers should be aware of high stress levels among mothers living in MRCs and aim at enhancing their living and housing conditions.

Stress-related eating in pregnancy? An RCT examining links between prenatal stress and food choices

BackgroundDiet quality during pregnancy is important for maternal health and offspring development. However, national dietary recommendations are not always met. A potential barrier for healthy food choices might be the experience of stress. Previous literature in non-pregnant populations suggests a negative effect of acute stress on diet quality. This preregistered study is the first to test whether an acute stressor leads to unhealthy food choices in pregnancy and examine the moderating role of stress, depressive and anxiety complaints in daily life. MethodPregnant women (N = 110, 3rd trimester) completed online self-reported surveys measuring stress, depressive and anxiety complaints in daily life. Hereafter, participants were invited for a laboratory visit, in which they were exposed to the Trier Social Stress Test or a control task. After this manipulation, self-reported and actual food choices and food intake were assessed. At the end of the visit, a hair sample was collected. Throughout the visit, visual analogue scales on negative affect were completed and saliva samples were collected. ResultsThe stress group experienced significantly more psychological stress than the control group during the experimental manipulation. Main regression analyses showed that the acute laboratory stressor did not cause unhealthy food choices in the third trimester of pregnancy. In fact, the stress group chose fewer unhealthy foods and consumed fewer kilocalories compared to the control group. Additionally, the findings point at a moderating role of depressive and stress complaints in daily life on food choices within the control group: higher scores were related to more unhealthy food choices and more kilocalories consumed. DiscussionAs this was the first study to test the effect of an acute stressor on food choices in pregnant women, more research is needed to obtain a better understanding of stress-related eating in pregnancy. This knowledge may inform future interventions to support pregnant women in improving their diet quality.

Is there a relationship between abuse of alcohol and illicit drugs seen in hair results?

Combined use of alcohol and illicit drugs is a serious health and social problem. In this study, it was examined, whether a relationship between alcohol and drug abuse can be ascertained by comparison of alcohol marker and drug concentrations in hair. In the frame of a social support system for families with parental abuse of illicit drugs, hair samples were analyzed between 2011 and 2022 for methadone, heroin (6-acetylmorphine), cocaine, amphetamine, ecstasy (MDMA), cannabinoids (THC), and the alcohol markers ethyl glucuronide (EtG) and ethyl palmitate (EtPa). For 1314 hair samples from adolescent and adult family members, the hair results show a prevalence of combined occasional or regular drug use and social or abusive alcohol use of 41%-60% except heroin (35%). The drug concentrations were statistically compared in the three categories of abstinence or moderate drinking, social drinking, and alcohol abuse. For the most frequently detected drug cocaine (n = 703), a significant increase of the concentrations with rising alcohol consumption was found. The frequent detection of cocaethylene proved the preferred simultaneous intake of both substances. For THC (n = 489), no significant difference between the alcohol consumer groups was seen. Concerning the less frequently detected methadone (n = 89), 6-acetylmorphine (n = 92), amphetamine (n = 123), and MDMA (n = 105), no clear trend between drug and alcohol marker results was determined. It is concluded that the evaluation of hair results is an appropriate way to study the extent of combined drug-alcohol consumption and complements other studies based on acquisition of consumption data by interview or questionnaire.

Triaging of hair samples using fluorescent in situ detection

ABSTRACT DiamondTM Nucleic Acid Dye (DD) has been evaluated for visualizing DNA material on various evidence types, including nuclei in plucked hair roots. While plucked hair roots exhibit a rapid DNA visualization process, shed hairs, even when stained with DD, pose challenges due to the lack of cell nuclei. In the absence of clear cell nuclei, the sole indicator of DNA presence is the fluorescent signal from DD bound to DNA. This study aimed to assess the stability of the fluorescent signal in shed hairs, revealing a rapid decline within 2–3 min post-staining, likely attributed to the cell-free nature of the DNA present on the hair root. Consequently, immediate microscopic visualization and imaging post-staining are crucial during shed hair examination.

Analysis of the hydration water on the surface of human hair using a combination of infrared absorption vibrational spectroscopy and multivariate curve resolution

Modern society's keen regard for aesthetics made hair products an integral part of a multi‐billion‐dollar cosmetic industry. Hair care products (e.g., shampoos and conditioners) and chemical treatments (e.g., bleaching and permanent waving) result in various effects on the morphological attributes of hair. Generally, water adsorbed on the hair surface is known to significantly dictate the hair's mechanical characteristics (smoothness and friction), and hair's macroscopic wettability has been commonly used to indicate its surface properties. However, an approach to selectively characterize the hydration water in the hair surface is required to accurately understand the intermolecular events between the hair and its vicinal water. In this paper, we successfully obtained the infrared (IR) absorption spectra of the hydration water of human hair. We employed the multivariate curve resolution‐alternating least square (MCR‐ALS) method to separate the hydration and bulk water spectra from the whole spectra. Comparing the IR spectra of the hydration water of chemically untreated and bleached hair samples, we conclude that water molecules form strong hydrogen bonds with the bleached hair surface due to the destruction of the hair's hydrophobic outer layer and the consequent formation of hydrophilic residues.

Detection and Imaging of Exposure-Related Metabolites and Xenobiotics in Hard Tissues by Laser Sampling and Mass Spectrometry.

The utility of two novel laser-based methods, laser ablation electrospray ionization (LAESI) and laser desorption ionization (LDI) from silicon nanopost array (NAPA), is explored via local analysis and mass spectrometry imaging (MSI) of hard tissues (tooth and hair) for the detection and mapping of organic components. Complex mass spectra are recorded in local analysis mode from tooth dentin and scalp hair samples. Nicotine and its metabolites (cotinine, hydroxycotinine, norcotinine, and nicotine) are detected by LAESI-MS in the teeth of rats exposed to tobacco smoke. The intensities of the detected metabolite peaks are proportional to the degree of exposure. Incorporating ion mobility separation in the LAESI-MS analysis of scalp hair enables the detection of cotinine in smoker hair along with other common molecular species, including endogenous steroid hormones and some lipids. Single hair strands are imaged by MALDI-MSI and NAPA-LDI-MSI to explore longitudinal variations in the level of small molecules. Comparing spectra integrated from NAPA-LDI-MSI and MALDI-MSI images reveals that the two techniques provide complementary information. There were 105 and 82 sample-related peaks for MALDI and NAPA, respectively, with an overlap of only 16 peaks, indicating a high degree of complementarity. Enhanced molecular coverage and spatial resolution offered by LAESI-MS and NAPA-LDI-MSI can reveal the distributions of known and potential biomarkers in hard tissues, facilitating exposome research.

Design, Development and Evaluation of Methi-Shikakai Herbal Shampoo

Shikakai, scientifically known as Acacia concinna, is a traditional Indian herb widely used for hair care due to its cleansing and conditioning properties. This research paper aims to Design, develop and evaluation of a shampoo incorporating shikakai extract, assessing its efficacy in terms of cleansing ability, hair conditioning, and overall performance. The formulation process involves selecting appropriate surfactants, additives, and optimizing concentrations to achieve desired attributes. Evaluation methods include physical characterization, such as pH, viscosity, and foam ability, as well as performance testing through sensory evaluation and hair analysis. The results of this study will provide valuable insights into the development of herbal-based shampoos and their potential benefits for hair health and maintenance.

Stability and inter-family associations of hair endocannabinoid and N-acylethanolamines across the perinatal period in mothers, fathers, and children

Analysis of endocannabinoids (ECs) and N-acylethanolamines (NAEs) in hair is assumed to retrospectively assess long-term EC/NAE concentrations. To inform their use, this study investigated stability of EC/NAE hair concentrations in mothers, fathers, and their children across the perinatal period as well as associations between family members. In a prospective cohort study, EC (AEA, 1-AG/2-AG) and NAE (SEA, PEA, OEA) levels were quantified in hair samples taken four times in mothers (n = 336) and their partners (n = 225) from pregnancy to two years postpartum and in offspring (n = 319) from shortly after birth to two years postpartum. Across the perinatal period, maternal and paternal hair ECs/NAEs showed poor multiple-test consistency (16–36%) and variable relative stability, as well as inconsistent absolute stability for mothers. Regarding children, hair ECs/NAEs evidenced poor multiple-test consistency (4–19%), no absolute stability, and either no or variable relative stability. Hair ECs/NAEs showed small to medium significant associations across the perinatal period within couples and parent–child dyads. Findings suggest hair ECs/NAEs during the perinatal period possess variable stability in adults, albeit more stability in fathers than mothers in this time. This highlights the need to further investigate factors associated with changes in hair ECs/NAEs across time. The first two years of life may be a dynamic phase for the endocannabinoid system in children, potentially characterized by complex within-family correspondence that requires further systematic investigation.

Relationships among cortisol, perceived stress, and dental caries experience in adolescents and young adults.

Stress can impact mental and physical health, especially during adolescence and young adulthood. Previous studies have shown that salivary cortisol levels are elevated in both severe dental caries and periodontal disease. The role of stress in periodontal disease has been studied, but the extent of its contribution to dental caries is less well understood, especially in this age group. The present study aimed to assess the association between perceived stress, cortisol levels (in hair and saliva) and overall caries experience of adolescents and young adults aged between 15 and 25 years. Hair and saliva samples were obtained from 93 participants (age range=15-25 years) free of periodontal disease. Cortisol concentrations in hair and saliva were determined using a competitive enzyme-linked immunosorbent assay. Participants completed a perceived stress questionnaire and underwent full-mouth oral examination by a calibrated examiner. Dental caries experience was based on the decayed, missing, and filled teeth (DMFT) index. In addition, sociodemographic variables were recorded. Univariate and multivariable binary logistic regressions were used to assess the relationships of interest. There were significantly higher hair cortisol levels (p=0.042) and perceived stress scale (PSS) scores (p=0.026) in individuals with dental caries experience (DMFT≥1) than in those without (DMFT=0). However, there was no significant difference in salivary cortisol concentration (p=0.302). A binary logistic regression revealed that higher hair cortisol levels and greater scores on the perceived stress scale were associated with an increased odds of having experienced dental caries (OR=4.08, 95% CI 1.04, 15.96; OR=1.65, 95% CI 1.04, 2.63; respectively). In contrast, no significant association was found between dental caries and salivary cortisol concentration (OR=0.31, 95% CI 0.02, 4.23). Using multivariable regression models, caries experience was found to be significantly associated with both hair cortisol levels and PSS scores. These associations remained statistically significant even after adjusting for confounding sociodemographic variables. In the absence of periodontal disease, hair cortisol levels have a significant association with dental caries experience, whereas salivary cortisol concentrations do not. Hair cortisol levels may reflect the chronic physiological burden imposed by exposure to detrimental stressors.

The application of statistical and novel unsupervised machine learning methodology to forensic hair analysis

ABSTRACT Hair colour is a valuable feature in forensic hair analysis and hair comparisons. Five hundred microscopic images of hair shafts were taken and for each image and colour model (RGB, CIE XYZ and CIE L*a*b*) values for each image were determined. The discriminating power of the three colour model values using statistical and unsupervised machine learning methods was evaluated. Additionally, the discriminating power of the images of the same hair shafts using unsupervised machine learning methods was evaluated. All methods were compared to determine which method had the greatest discriminating power to best distinguished between participants and accurately assigned hair to an individual and assist in forensic hair comparisons. The RGB colour model demonstrated the highest discriminating power of the colour model values while the CIE L*a*b* model achieved complete discrimination with a reduced number of participants. The unsupervised k-means model yielded similar results. Unsupervised PCA/k-means and agglomerative clustering models demonstrated low discrimination power of the images, suggesting the existence of additional features within the data beyond colour. This research highlights the significance of the incorporation of colour values in forensic hair comparisons and for further exploration of the incorporation of other hair features, beyond colour values.

OA29 Epigenetic regulation of IL-4 promoter targeting p300 attenuating intervertebral disc degeneration and pain by inhibiting IL-1β

Abstract Background/Aims Low back pain (LBP) is a prevalent condition primarily caused by intervertebral disc degeneration (IVDD), which imposes a substantial social and medical burden. Effective targeted treatments to prevent the progression of IVDD and alleviate LBP are still lacking. p300, a critical member of the histone acetyltransferase (HAT) family, is involved in the regulation of inflammation. This study aims to investigate the role of p300/IL-4 in IVDD and pain and elucidate the underlying molecular mechanism. Methods Human intervertebral disc samples were collected and graded based on the Pfirrmann grading scheme. A rat model of IVDD was established through posterior disc puncture, and various treatments were administered. Human nucleus pulposus cells (NPCs) were isolated and cultured, followed by assessments including qRT-PCR, Western blotting, immunofluorescence, and histopathological analyses. The mechanical and thermal hyperalgesia were assessed using von Frey hair tests and the plantar test, respectively. Chromatin immunoprecipitation (ChIP) and ChIP-qPCR were performed, and lentivirus transduction was used for p300 knockdown. Results We investigated the role of CREB binding protein (CBP)/p300 in IVDD. Degenerated nucleus pulposus (NP) tissues from IVDD patients exhibited a significant downregulation of p300 at both nucleic acid and protein levels, while CBP levels remained unchanged. Manipulating p300 expression in NPCs regulated matrix production, with p300 overexpression enhancing aggrecan and collagen II expression and knockdown leading to increased matrix-degrading proteins. In a rat IVDD model, activating p300 function with CTPB (p300-specific activator) alleviated IVDD and pain, while inhibiting p300 with C646 exacerbated IVDD and pain. Transcriptome analysis implicated IL-4 as a downstream effector of p300, and IL-4 demonstrated protective effects against IVDD and pain. Mechanistically, p300 was found to acetylate H3K27 at the IL-4 promoter, promoting its expression. Conclusion The novel findings of this study suggest that the p300/IL-4/IL-1β axis may represent a promising therapeutic target for IVDD and LBP. These results propose a hypothesis that, early in the inflammatory phase, NPCs may initiate a self-protective mechanism through p300, aiding itself in preserving a favourable metabolic microenvironment. This mechanism is primarily mediated by the expression of IL-4, which has the capacity to counteract IL-1β, rather than TNF-α. Disclosure H. Cui: None. Z. Zheng: None.

Seasonal Hair Glucocorticoid Fluctuations in Wild Mice (Phyllotis darwini) within a Semi-Arid Landscape in North-Central Chile.

Mammals in drylands face environmental challenges exacerbated by climate change. Currently, human activity significantly impacts these environments, and its effects on the energy demands experienced by individuals have not yet been determined. Energy demand in organisms is managed through elevations in glucocorticoid levels, which also vary with developmental and health states. Here, we assessed how anthropization, individual characteristics, and seasonality influence hair glucocorticoid concentration in the Darwin's leaf-eared mouse (Phyllotis darwini) inhabiting two areas with contrasting anthropogenic intervention in a semi-arid ecosystem of northern Chile. Hair samples were collected (n = 199) to quantify hair corticosterone concentration (HCC) using enzyme immunoassays; additionally, sex, body condition, and ectoparasite load were recorded. There were no differences in HCC between anthropized areas and areas protected from human disturbance; however, higher concentrations were recorded in females, and seasonal fluctuations were experienced by males. The results indicate that animals inhabiting semi-arid ecosystems are differentially stressed depending on their sex. Additionally, sex and season have a greater impact on corticosterone concentration than anthropogenic perturbation, possibly including temporal factors, precipitation, and primary production. The influence of sex and seasonality on HCC in P. darwini make it necessary to include these variables in future stress assessments of this species.