Hair Samples Research Articles

Effect of Eucalyptus Extract on Bleach Hair

Purpose: This study aims to investigate the effects of eucalyptus oil on damaged hair. Methods: Eucalyptus formulations were prepared by adding 0, 3, 6, or 9 g of eucalyptus extract, and these formulations were applied to level 8 bleached hair samples. Various parameters were then measured and compared in the treated bleached hair. The impact of eucalyptus extract on hair brightness was assessed by measuring L * values using a color difference meter. Additionally, tensile strength, absorbance (determined using methylene blue), and gloss of the bleached hair were measured. Results: Measurement analysis showed that L * values increased as the content of eucalyptus extract applied to bleached hair increased. A statistically significant difference in brightness was observed among 8L(3), 8L(6), and 8L(9) samples. Furthermore, average tensile strength of the hair increased as extract content increased, although the difference did not reach statistical significance. Absorbance analysis revealed a significant difference between the average value and statistical analysis value for each sample, indicating that eucalyptus extract affects the absorbance of bleached hair. Gloss analysis also revealed differences in average values as extract content increased, with a significant difference observed at 8L(6) and 8L(9) but not 8L(3), suggesting that eucalyptus extract affects hair gloss in a content-dependent manner. Conclusion: Statistical analysis of average values revealed that eucalyptus extract affected bleached hair in terms of brightness, absorbance, and gloss, with different eucalyptus extract contents having different effects on the hair. Future studies should investigate the effects of various other natural extracts on bleached hair.

Cumulative environmental stress and emerging cardiometabolic risk during childhood.

To prospectively evaluate the relationship between cumulative environmental stress and cardiometabolic risk in middle childhood, and to examine whether hair cortisol, a measure of hypothalamic pituitary adrenal-axis activity, mediates this relationship. In a cohort of children from low-income households (n = 320; 59% Hispanic, 23% Black, body mass index (BMI) percentile >50th at enrollment), environmental stressors including family and neighbourhood factors representing disadvantage/deprivation, and cortisol concentrations from hair samples, were measured over five timepoints beginning when children were 2-4 years old. Cardiometabolic risk factors (i.e., BMI, blood pressure, lipids, blood sugar, C-reactive protein) were measured at the final timepoint when children were 7-11 years of age. In adjusted logistic regression models, greater cumulative environmental stress was associated with a higher likelihood of elevated cardiometabolic risk in middle childhood (p = 0.01). Children from minoritized racial/ethnic groups had a higher prevalence of both stressors and cardiometabolic risk factors. Cumulative environmental stress was associated with higher hair cortisol concentrations (p < 0.01). However, hair cortisol was not directly associated with cardiometabolic risk factors and did not explain the association between environmental stress and cardiometabolic risk in causal mediation analysis. The influence of cumulative stress on cardiometabolic health can be observed in middle childhood and may contribute to cardiometabolic health disparities, highlighting the importance of public health interventions to mitigate disadvantage.

Development of a Predictive Model for Iron Levels in Bovine Muscle Tissue Using Hair as a Predictor.

The assessment of iron levels in cattle muscle tissue is crucial for livestock management because it influences both animal health and meat quality, key factors in sustainable development. This study aimed to develop an optimal model for noninvasively predicting the iron content in Hereford cattle muscle tissue, contributing to a comprehensive understanding of the animals' elemental status. The research involved the atomic absorption analysis of muscle tissue and hair samples from cattle. A regression model was constructed using the least squares method to identify the most effective approach. These findings have ecological applications, aiding in evaluating environmental health and establishing acceptable iron thresholds for animals. The proposed mathematical model utilizing biomarkers (levels of Mg, K, Fe, Al, Cr in hair) will allow for the assessment of iron levels in cattle muscle tissue throughout the period of productive use, with the possibility of adjustment and tracking the changes in elemental status over time. The utilization of the developed method will enable the diagnosis of animal elementosis and assessment of the iron level burden. Subsequently, this will allow for the improvement of the qualitative characteristics of the final product. Thus, the obtained data contribute to fundamental knowledge regarding the content and variability of iron levels in the muscle tissue of cattle.

FTIR spectroscopy for assessment of hair from lung cancer patients and its application in monitoring the chemotherapy treatment effect

Lung cancer is the most common cancer and the leading cause of death in China. The current gold standard for clinical lung cancer diagnosis is based on histopathological examination of tumors, but it has the limitation for easy operation and convenient applications. Therefore, researchers are still striving to develop other tools and methods for non-invasive and rapid assessment of the health conditions of lung cancer patients. Hair, as a reflection of the metabolism of the body, is closely related to human health conditions. In principle, Fourier-transform infrared (FTIR) spectroscopy can probe the major chemical compositions in the hair. However, as indicated by previous studies, there is still the challenge to make good use of FTIR spectroscopy for achieving reliable analysis of hair from cancer patients. In this study, hair samples from 82 lung cancer patients were collected and subjected to FTIR measurements and analysis, which showed the protein content in the hair is closely related to the protein content in the blood serum of patients, and the contents of protein and lipid are statistically lower in the lung cancer patients. Furthermore, we demonstrated that FTIR spectroscopy could be employed to monitor the hair of lung cancer patients undergoing chemotherapy, and confirmed that the FTIR spectra of the hair may reflect the resultant effect of the chemotherapy. As such, this work validates the way of using FTIR spectroscopy in hair analysis for the assistance of medical diagnosis of lung cancer as well as monitoring the conditions of the patients under the medical treatment.

An LC-MS/MS method for the determination of drugs of abuse included THC-COOH, EtG, and NPS, using a single hair extraction sample.

Hair analysis plays an important role in the determination of drugs of abuse in both forensic and clinical toxicology investigations. The analysis of different substances often requires the use of different sample preparation methods, thereby increasing the amount of hair sample and time required. In the present study, a fast method involving a combination of a single 25 mg hair extraction procedure and four liquid chromatography-tandem mass spectrometry methods using the same chromatographic phases and column was developed and validated. The target was the identification and quantification of various commonly abused drugs and their metabolites, including amphetamines, cocaine, opioids, cannabinoids, THC-COOH and EtG, and more than 140 new psychoactive substances, including synthetic cannabinoids, phenethylamines, synthetic opioids, methylphenidate, cathinone, piperidine, and tryptamines.

Study protocol: randomized controlled trial of an individualized music intervention for people with dementia in the home care setting

BackgroundStudies suggest that individualized music listening is an effective, non-pharmacological intervention for improving the quality of life of people with dementia in the institutional care setting. Noting that most people with dementia live at home, we conduct a randomized controlled trial to assess the feasibility and effectiveness of an app-based individualized music listening intervention for people with dementia in the home care setting. The intervention is delivered by family caregivers.MethodsWe will recruit N = 130 dyads consisting of one person with dementia living at home and their family caregiver. After a baseline assessment, dyads are randomly assigned by gender to either the intervention or control group. People with dementia in the intervention group listen to individualized music playlists for 20 min every other day for six weeks via the self-developed Individualized Music and Dementia app. The control group receives standard care. All dyads complete paper-and-pencil questionnaires six weeks before the start of the intervention (T0), directly before the intervention (T1), directly after the intervention (T2), and six weeks later (T3). During the intervention period, all caregivers also complete daily ecological momentary assessments via the app. During three home visits, a trained project member will observe the dyads and collect hair samples. After the intervention, semi-structured interviews will be conducted to collect information about participants’ experiences with the app and intervention. The primary outcome is the attainment of individual goals established during the baseline assessment. Secondary outcomes are the well-being, physiological stress and quality of life of people with dementia and their caregivers; people with dementia’s behavioural and psychological symptoms of dementia, resistance during care, and reactions to the music; caregivers’ burden of care, positive aspects of care, and caregiving self-efficacy; and the quality of the caregiver-care recipient interaction.DiscussionOur study will assess the extent to which an app-based individualized music listening intervention is feasible and effective for enhancing the well-being and quality of life of people with dementia living at home and their family caregivers.Trial registrationGerman Clinical Trials Register DRKS00025502 and ISRCTN registry ISRCTN68084105, https://doi.org/10.1186/ISRCTN68084105

Melanin granules morphology and distribution in human black hair investigated by focused ion beam scanning electron microscopy: Differences between Asian and Caucasian hair

Melanin granules (melanosomes) in Asian and Caucasian black hairs were investigated by focused ion beam scanning electron microscopy (FIB-SEM). This technique facilitates a direct evaluation of the three-dimensional distribution and morphology of melanin granules without requiring their isolation from hair. Three-dimensional reconstructed images of melanin granule distribution in hair samples were obtained using serial SEM images observed by FIB-SEM. Melanin granules in black hair tended to be three-dimensionally dense in the outer periphery of the cortex. The morphometric parameters of melanin granules were calculated using the reconstructed three-dimensional images. The results confirmed that melanin granules in Caucasian black hair were much smaller those in Asian black hair. Moreover, it was indicated that the relative frequency distribution of the volume of melanin granules was significantly different between Asians and Caucasians.

Systematic web monitoring of drug test subversion strategies in the United States.

As negative drug tests are frequently a condition for employment, some people who use drugs will try to subvert the testing. In this study, systematic web monitoring was used to investigate how drug test subversion is discussed online. Posts pertaining to drug test subversion were obtained from public websites and the dark web (n= 634, July-December 2021). Most information from public websites came from Twitter (65%), and 94% of dark web posts were from Reddit. The posts were manually coded to extract quantitative and qualitative information about drug test subversion tactics. Most posts discussed urine drug tests (85%), followed by hair (11%) and oral fluid (2%), and the most discussed drugs were marijuana (72%) and cocaine (7.3%). Urine drug test subversion mainly pertained to specimen substitution, with synthetic urine or urine from another person. Another strategy was to mask diluted urine by ingesting creatine. Urine adulteration was rarely discussed. Hair test subversion involved harsh treatments with products such as bleach, baking soda, and/or detergent. Hair removal was also discussed. Oral fluid test subversion focused on removing drugs from the oral cavity through vigorous brushing of teeth and tongue as well as the use of mouthwash, hydrogen peroxide, gum, and commercial detox products. This study highlights subversion strategies used by donors. Although little evidence was provided as to the effectiveness of these strategies, this information may help guide future studies and development of specimen validity testing to minimize the impact of drug test subversion attempts.

Glucocorticoid hormones in relation to environmental exposure to bisphenols and multiclass pesticides among middle aged-women: Results from hair analysis

Bisphenols and pesticides have been shown to alter circulating glucocorticoids levels in animals, but there is limited human data. Moreover, measurements from biological fluids may not be able to reflect long-term status of non-persistent pollutants and glucocorticoids due to the high variability in their levels. Using hair analysis, we examined the associations between glucocorticoid hormones and environmental exposure to multi-class organic pollutants among a healthy female population aged 25–45 years old. Concentrations of four glucocorticoids, four polychlorinated biphenyl congeners (PCBs), seven polybrominated diphenyl ether congeners (PBDEs), two bisphenols and 140 pesticides and their metabolites were measured in hair samples collected from 196 Chinese women living in urban areas. Due to the low detection frequency of some pollutants, associations were explored only on 54 pollutants, i.e. PCB 180, bisphenol A, bisphenol S and 51 pesticides and their metabolites. Using stability-based Lasso regression, there were associations of cortisol, tetrahydrocortisol, cortisone, and tetrahydrocortisone with 14, 10, 13 and 17 biomarkers of exposure to pollutants, respectively, with bisphenol S, p,p’-dichlorodiphenyldichloroethylene, diethyl phosphate, 3,5,6-trichloro-2-pyridinol, thiamethoxam, imidacloprid, fipronil, tebuconazole, trifluralin, pyraclostrobin and 1-(3,4-dichlorophenyl)-3-methylurea being associated with at least three of the four hormones. There were also associations between cortisone/cortisol molar ratio and pollutants, namely dimethyl phosphate, 3-methyl-4-nitrophenol, carbofuran, λ-cyhalothrin, permethrin, fipronil, flusilazole, prometryn and fenuron. Some of these relationships were confirmed by single-pollutant linear regression analyses. Overall, our results suggest that background level of exposure to bisphenols and currently used pesticides may interfere with the glucocorticoid homeostasis in healthy women.

Abstract 1003: Contact registry for health-related cancer research: Promoting inclusion in research

Abstract Contact Registries can serve as key tools in connecting community members to cancer health research opportunities. Members of underrepresented groups who enroll in a contact registry can choose to participate in studies they find interesting, provided they are an ideal candidate for participation. However, limited information exists regarding the types of studies underrepresented groups would want to participate in. The Florida-California Cancer Research, Education, and Engagement (CaRE2) Health Equity Center Community Outreach Core (COC) created a contact registry of community members self-identifying as Black/African American (B/AA) and/or Hispanic/Latinx (H/L) persons who are interested in learning about future research studies conducted at CaRE2 institutions. The CaRE2 Contact Registry was implemented in August 2022 by the CaRE2 COC, one of the six (6) key cores within the CaRE2 Center. COC’s primary objective is to increase the number of persons participating in cancer research, which ultimately produces findings more applicable to the broader, diverse population of B/AA and H/L communities in both Florida and California. Our study team promotes the registry at local community events and through our center’s social media accounts and website (https://care2healthequitycenter.org/the-care2-contact-registry/). Recruitment consists of both in-person and online methods provided in both Spanish and English with data stored on REDCap, an online data repository system. For in-person enrollment, a consent/authorization form and OPT-IN survey are completed; meanwhile, our online recruitment requires additional screening to ensure eligibility. Eligibility requires that the person resides in 1) either California or Florida, 2) be 18+ years old, and 3) identify as B/AA or H/L. In addition to collecting contact and demographic information, participants can choose their research study interests. For example, they can choose to participate in surveys, community forums, focus groups, a cancer advocacy training program, and/or to provide a hair, saliva, or blood sample. A $10.00 gift card, either in a physical or electronic format, was provided to each confirmed enrollee. As of November 13, 2023, 1,269 persons have enrolled, representing 63% of the 2,000 enrollment goal. While 92% of registry enrollees are willing to participate in health research involving surveys, only 20% are willing to participate in health research studies requiring saliva (23%), hair (22%), or blood (20%) donations. In conclusion, registry enrollees, regardless of race or ethnicity, have a high interest in participating in studies involving completing surveys or attending focus groups. However, efforts must continue to increase participation willingness for research involving biospecimen donation. Future efforts will also include connecting enrollees to cancer health-related research studies of their interest. Citation Format: Fern Webb, IIeana Guzman, Brooke Hensel, Eduardo Ibarra, Carolina Aristizabal, John Luque, Rosa Barahona, Diana Wilkie, Mariana C. Stern, Lourdes Baezconde-Garbanati, Sandra Suther. Contact registry for health-related cancer research: Promoting inclusion in research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1003.

Single hair analysis for gamma-hydroxybutyric acid-Method optimization, validation, and application.

As gamma-hydroxybutyric acid (GHB) underlies fast metabolization, its determination from hair may presumably offer a detection window superior to that of body fluids. Due to the wide range of endogenous concentration levels, the evidence of an exogenous ingestion is challenging. As already shown for other drugs, the temporal resolution obtained by applying single hair microanalysis provides further information. Therefore, a method for the extraction and quantification of GHB in 2-mm hair segments (seg) was optimized and validated (limit of detection [LOD]: 2.5 pg/seg, lower limit of quantification [LLOQ]: 5 pg/seg), and five single hairs were examined, each for three non-users and for three (alleged) users. A major challenge was the choice of appropriate extraction tubes without remains of GHB. In two samples from non-users, GHB could not or could only be detected in trace amounts. In the third sample, concentrations between the LOD and 31.1 pg/seg (mean: 9.5, median: 8.4; each pg/seg) were detected with decreasing values towards the tips. In two samples of persons with assumed GHB intake, maximum concentrations of 6.8 and 30.7 pg/seg were measured, but no significant concentration peaks indicating a single ingestion could be observed. The third sample showed concentrations of 7.6-55.2 pg/seg (mean: 28.8, median: 29.6; each pg/seg). In this case, the obtained profiles showing at least two reproducible concentration maxima between 20 and 40 mm point to an ingestion of GHB. The concentration profiles from single hairs were reproducible in each case, reflecting the concentration course of routine 1-cm segmental analysis. These are the first results published on GHB testing in segmented single hairs, and the results must be verified further.

Is the Javan tiger Panthera tigris sondaica extant? DNA analysis of a recent hair sample

Abstract The Javan tiger Panthera tigris sondaica and the Bali tiger P. tigris balica were categorized as Extinct on the IUCN Red List in both 2003 and 2008, leaving only the Sumatran subspecies P. tigris sumatrae extant in Indonesia. There have, however, been occasional, more recent reports of the Javan tiger but without conclusive evidence. Here, a potential observation in 2019 of a Javan tiger in a community plantation near the village of Cipendeuy in the forest of South Sukabumi, West Java, and a single hair found on a fence nearby, are assessed. The cytochrome b mitochondrial DNA (mtDNA) gene sequence of the putative Javan tiger hair were compared with that of a Javan tiger specimen in Museum Zoologicum Bogoriense, collected in 1930; hair samples of several tiger subspecies and the Javan leopard Panthera pardus melas were used as controls. The results showed that the genetic distances (d) of the putative Javan tiger hair with the Sumatran, Bengal P. tigris tigris and Amur P. tigris altaica tigers and the Javan leopard are 0.074 ± SE 0.009, 0.071 ± SE 0.009, 0.072 ± SE 0.009 and 0.088 ± SE 0.010, respectively, whereas the genetic distance of the putative Javan tiger hair with the Javan tiger museum specimen is 0.040 ± SE 0.006. In addition, phylogenetic trees showed that the putative Javan tiger hair sample belongs to the same group as the museum specimen of the Javan tiger, but is differentiated from other tiger subspecies and the Javan leopard. Whether the Javan tiger still occurs in the wild needs to be confirmed with further genetic and field studies.

Long-Term Glucocorticoid Exposure and Incident Cardiovascular Diseases-The Lifelines Cohort.

Long-term glucocorticoid levels in scalp hair (HairGCs), including cortisol and the inactive form cortisone, represent the cumulative systemic exposure to glucocorticoids over months. HairGCs have repeatedly shown associations with cardiometabolic and immune parameters, but longitudinal data are lacking. We investigated 6341 hair samples of participants from the Lifelines cohort study for cortisol and cortisone levels and associated these to incident cardiovascular diseases (CVD) during 5 to 7 years of follow-up. We computed the odds ratio (OR) of HairGC levels for incident CVD via logistic regression, adjusting for classical cardiovascular risk factors, and performed a sensitivity analysis in subcohorts of participants < 60 years and ≥ 60 years of age. We also associated HairGC levels to immune parameters (total leukocytes and subtypes). Hair cortisone levels (available in n = 4701) were independently associated with incident CVD (P < .001), particularly in younger individuals (multivariate-adjusted OR 4.21, 95% CI 1.91-9.07 per point increase in 10-log cortisone concentration [pg/mg], P < .001). All immune parameters except eosinophils were associated with hair cortisone (all multivariate-adjusted P < .05). In this large, prospective cohort study, we found that long-term cortisone levels, measured in scalp hair, represent a relevant and significant predictor for future CVD in younger individuals. These results highlight glucocorticoid action as possible treatment target for CVD prevention, where hair glucocorticoid measurements could help identify individuals that may benefit from such treatments.

Using surface-enhanced Raman spectroscopy to probe artificial dye degradation on hair buried in multiple soils for up to eight weeks

The discovery of clandestine burials poses unique challenges for forensic specialists, requiring diverse expertise to analyze remains in various states. Bones, teeth, and hair often endure the test of time, with hair particularly exposed to the external environment. While existing studies focus on the degradation of virgin hair influenced by soil pH and decomposition fluids, the interaction between artificial dyes on hair and soil remains underexplored. This paper introduces a novel approach to forensic hair analysis that is based on high-throughput, nondestructive, and non-invasive surface-enhanced Raman spectroscopy (SERS) and machine learning. Using this approach, we investigated the reliability of the detection and identification of artificial dyes on hair buried in three distinct soil types for up to eight weeks. Our results demonstrated that SERS enabled the correct prediction of 97.9% of spectra for five out of the eight dyes used within the 8 weeks of exposure. We also investigated the extent to which SERS and machine learning can be used to predict the number of weeks since burial, as this information may provide valuable insights into post-mortem intervals. We found that SERS enabled highly accurate exposure intervals to soils for specific dyes. The study underscores the high achievability of SERS in extrapolating colorant information from dyed hairs buried in diverse soils, with the suggestion that further model refinement could enhance its reliability in forensic applications.

Infant exposure to drugs of abuse investigated by hair analysis.

Infant exposure to drugs of abuse represents a worldwide problem whose extent is difficult to estimate. Despite the potentially serious health consequences, few data concerning exposure in children under 1 year of age are available. Since in clinical and forensic settings, neonatal and infant hair testing represents a useful method for investigating suspected drug exposures, an observational retrospective study was performed on hair analysis of children under 1 year of age evaluated at the University Hospital of Padova between 2018 and 2022 with the aim of estimate the extent and define the characteristics of this phenomenon in the reference setting. The sample included 102 infants. Chemical-toxicological analyses were requested in 38 cases (37.3%) because of clinically suspicious symptoms of the child (e.g., neuropsychiatric symptoms and suspected neonatal abstinence syndrome) and in 64 cases (62.7%) because of other reasons (e.g., maternal drug history, at-risk environment, and suspected maltreatment). Based on the presence or absence of symptoms in the request, the sample was subdivided into two groups. Hair analysis in these two showed the presence of drug of abuse, respectively, in 44.7% and 67.2% of the cases (p= 0.026). Cocaine was the most frequently detected substance, followed by opiates, and it was detected less frequently in cases investigated for suspicious clinical symptoms (p< 0.05). The results confirm the difficulties in interpreting the clinical picture and in defining the extent of exposure to drugs of abuse. An integrated assessment is fundamental to interpret the case and achieve adequate care of the child.

Analysing and quantifying chronic stress-associated endogenous steroids in hair samples.

In previous studies, various steroids have been associated with stress and have therefore been quantified to investigate stress-related questions. Since the main stress-related steroid cortisol follows a circadian rhythm, often hair is analysed to quantify this steroid. Further, hair analysis gives the unique possibility of long-time monitoring by analysing a certain segment of hair, since hair grows on average 1 cm per month. Hair is a difficult matrix due to the complex sample preparation with many steps including washing and grinding, followed by various extraction steps. Additionally, steroids are endogenous and are therefore present in the hair matrix. Hence, no analyte free matrix is available, which is needed for the quantification via external calibrators. To overcome this problem, the so-called surrogate methods can be used, for which a 13 C3 labelled or deuterated reference compound of the steroid of interest is used for quantification. In the present study, a surrogate method was developed and fully validated for the quantitative analysis of seven steroids in human hair. Validation experiments showed that the method is further suitable for semi-quantitative analysis of estradiol. However, it is not suitable for the analysis of androsterone and DHEAS. The method was successfully used to analyse steroids in a comprehensive study of 360 adolescent hair samples, enabling research into stress markers.

Human biomonitoring of trace metals from different altitudinal settings of Pakistan.

Human biomonitoring of toxic trace elements is of critical importance for public health protection. The current study aims to assess the levels of selected trace metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) into paired human nail and hair samples (n = 180 each) from different altitudinal setting along the Indus River, and which were measured by using inductively coupled plasma mass spectrometry (ICP-MS). The human samples (hair and nail) were collected from four different ecological zones of Pakistan which include frozen mountain zone (FMZ), wet mountain zone (WMZ), riverine delta zone (RDZ), and low-lying southern areas (LLZ). Our results showed the following occurrence trends into studied hair samples: higher values (ppm) of Zn (281), Co (0.136), and Mn (5.65) at FMZ; Cr (1.37), Mn (7.83), and Ni (1.22) at WMZ; Co (0.15), Mn (11.89), and Ni (0.99) at RDZ; and Mn (8.99) and Ni (0.90) at LLZ. While in the case of nails, the levels (ppm) of Mn (9.91) at FMZ and Mn (9.38, 24.1, and 12.5), Cr (1.84, 3.87, and 2.33), and Ni (10.69, 8.89, and 12.6) at WMZ, RDZ and LLZ, respectively, showed higher concentration. In general, among the studied trace elements, Mn and Ni in hair/nail samples were consistently higher and exceeded the WHO threshold/published reference values in most of the studied samples (> 50-60%) throughout the Indus basin. Similarly, hair/nail Pb values were also higher in few cases (2-10%) at all studied zones and exceeded the WHO threshold/published reference values. Our area-wise comparisons of studied metals exhibited altitudinal trends for Cd, Cr, Zn, and Mn (p < 0.05), and surprisingly, the values were increasing from south to north (at higher altitudes) and indicative of geogenic sources of the studied toxic elements, except Mn, which was higher at lower floodplain areas. Estimated daily intake (EDI) values showed that food and drinking water had the highest contribution towards Zn, Cu, Mn, and Ni and accumulation at all studied zones. Whereas, dust also acts as the main exposure route for Mn, Co, Cr, and Cd followed by the food, and water.

Long-Term Environmental Methylmercury Exposure Is Associated with Peripheral Neuropathy and Cognitive Impairment among an Amazon Indigenous Population.

Widespread contamination of the Amazon basin with mercury has been reported to occur since at least the mid-80s due to heavy gold mining activity. Although initial studies have indicated that this may lead to deleterious neurological consequences to the indigenous populations living in the region, further research is needed to better characterize the neurological burden of such long-term exposure. With this aim, a cross-sectional exploratory study has been conducted with the Yanomami indigenous population residing in a northern Amazon region. All participants underwent a structured interview; detailed neurological examination, including assessment for cognitive, motor, coordination, and sensory functions; and laboratorial testing for serum hemoglobin, blood glucose, and methylmercury levels in hair samples. This study enrolled 154 individuals of 30.9 ± 16.8 years of age, of which 56.1% were female. Mean methylmercury levels in hair were 3.9 ± 1.7 µg/g. Methylmercury levels in hair > 6.0 µg/g were found in 10.3%. Among participants with hair methylmercury levels ≥ 6.0 μg/g, the prevalences of peripheral neuropathy and reduced cognitive performance were, respectively, 78.8% (95%CI 15-177%, p = 0.010) and 95.9% (95%CI 16-230.8%, p = 0.012) higher than those of individuals with lower levels. These results suggest that chronic mercury exposure may lead to significant and potentially irreversible neurotoxicity to Yanomami population living in the northern Amazon basin.

It’s all in the hair: Association between changes in hair cortisol concentrations in reaction to the COVID-19 pandemic and post-traumatic stress symptoms in children over time

After exposure to a stressful/traumatic event, some individuals will develop post-traumatic stress symptoms (PTSS). In adults, low cortisol levels appear to be a risk factor for the development of PTSS. Indeed, both lower pre-trauma cortisol levels and low cortisol levels in the aftermath of a traumatic event have been associated with greater PTSS. In contrast, studies conducted in children showed that elevated cortisol levels shortly after trauma exposure are associated with more severe post-traumatic stress symptomatology. The few studies that have examined how pre-trauma cortisol levels predict PTSS in children have found no effect. Given that a pandemic can induce PTSS in certain individuals, we investigated whether cortisol secretion prior to and in the early stages of the COVID-19 pandemic in Quebec (Canada) predicted PTSS in children. In June 2020, we collected a hair sample from 71 children (8–15 y/o, M = 11.65; 54.93% girls) without a history of psychopathology or exposure to previous traumatic events. Hair samples allowed us to derive cumulative measures of cortisol levels for the months prior to (from mid-December 2019 to mid-March 2020) and at the beginning of the pandemic (from mid-March 2020 to mid-June 2020). PTSS were assessed every 3 months between June 2020 (T1) and March 2021 (T4). The results showed that a greater increase in hair cortisol at the beginning of the pandemic predicted less PTSS at T1, with an increase in these symptoms over time. This study highlights the utility of using hair cortisol during future chronic stressful events to better understand its association with the evolution of distress.

Mercury in Fish and Human Hair and Estimated Dietary Intake in a Riverside Community of the Madeira River Basin in the Brazilian Amazon.

Mercury (Hg) is a chemical element that poses risks to human health due to its high toxicity and environmental persistence. We determined the total Hg (THg) and methyl Hg (MeHg) concentrations in hair samples from residents of the Demarcação District (Porto Velho, Rondônia) in the Brazilian Amazon, as well as in water and fish samples, to evaluate factors influencing human exposure. The average THg concentration in human hair was 7.86 ± 6.78 mg kg-1 and it was significantly higher in men, with an increasing trend related to age. There was no significant difference between female age groups. Human exposure to Hg through water was negligible compared to fish consumption. The average weekly intake estimates in the community varied between 1.54 and 4.62 μg kg-1, substantially higher than the recommended limit. The fish species with the highest amounts safe for daily consumption were herbivores and detritivores. Our results contribute to an understanding of how exposure to Hg affects the health of riverside populations and provide insights for new research to develop methods to mitigate such exposure and thus improve the quality of life of Amazonian people.