Testing for Kratom alkaloids in fingernail clippings - not only mitragynine.

Kratom (Mitragyna speciosa) is a species of large tree that grows in Southeast Asia and is part of the Rubiaceae family. Its fresh leaves are harvested for their medicinal properties and used for their psychoactive effects. Kratom contains many biologically active alkaloids, including mitragynine and 7-OH-mitragynine, which are considered the two most important psychoactive components and constitute approximately 66% and 2% of the total alkaloid content. Other alkaloids are present in the plant, such as speciogynine, speciociliatine and paynantheine, but have less psychoactive activity. Over the past decade, the sale of kratom powder has increased on the Internet. This led to a significant increase in forensic cases. Given the lack of data existing in the literature, and the total absence of data in nails, the authors report a study to determine the best target alkaloids for documenting kratom consumption in this matrix. Fingernail clippings from a supposed kratom powder user were analyzed after liquid-liquid extraction, chromatography separation using a HSS C18 column and performed on an ultra-high performance liquid chromatography coupled to a tandem mass spectrometer. In the specimen, mitragynine was quantified at 229 pg/mg, speciogynine and paynantheine were both quantified at 2 pg/mg, and speciociliatine was quantified at 19 pg/mg. 7-OH-mitragynine was not detected. The interpretation of these concentrations is complex, since there is currently no reference in the literature, as this is the first identification of mitragynine and other kratom alkaloids in nails. Nevertheless, in view of the high concentration of mitragynine, the subject seems to be a repetitive user of kratom. According to the measured concentrations, it seems that mitragynine remains the best target to document kratom consumption, but the identification of the other alkaloids would enhance the specificity of the test.

Benchtop x-ray fluorescence to quantify elemental content in nails non-destructively.

Metals continue to impose health issues among world populations. A non-invasive alternative biomarker for assessment of metals and other elements has been explored in other studies using toenail samples. Some benefits of using toenails as biomarkers over blood samples include cost efficiency, ease of collection, and a longer biological half-life within samples. The objective of this study was to employ desktop XRF for the purpose of measuring metal concentrations in human nail samples, thus conducting a non-destructive assessment. These benefits paired with comparable accuracy in exposure detection could prove toenail samples to be a preferred biomarker for many studies. Current elemental quantification techniques in toenail samples could be improved. The standard practice for measuring metal exposure in toenails, inductively coupled plasma mass spectrometry (ICP-MS), has a counterpart in x-ray fluorescence. While maintaining similar quantification capabilities, x-ray fluorescence could provide decreased cost, preservation of samples, and ease of operation. Portable XRF machines have been tested for measuring toenail samples, but they have drastically increased detection limits in comparison to ICP-MS. New benchtop XRF systems should give comparable detection limits to ICP-MS. This study compares the benchtop XRF measurements of lead (Pb), copper (Cu), iron (Fe), and Selenium (Se) levels to that of ICP-MS measurements of toenail samples and calculates estimated detection limits for 23 other elements. We found strong correlations for the toenail lead (R2 = 0.92), copper (R2 = 0.95), selenium (R2 = 0.60), and iron (R2 = 0.77) comparison between desktop XRF and ICP-MS measurements. Median minimum detection limits over the 23 elements were found to be 0.2 µg/g using a 7.5-min measurement. Benchtop XRF provides a lower detection limit than previously studied portable XRF machines, which gives it the capability of accurately detecting almost any desired element in nail samples. Benchtop XRF provides a non-destructive alternative to ICP-MS in surveillance of nail samples.

A multi-collector ICP-MS method for quantification of plutonium, uranium, and americium in hair and nails of occupationally or medically exposed individuals.

The 239Pu, 238U, and 241Am concentrations and 239Pu/240Pu, 235U/238U, and 236U/238U atom ratios were measured in the hair and nail samples using a new method utilized TEVA, UTEVA, and DGA extraction chromatography and multi-collector ICP-MS. Samples were collected from individuals who donated their bodies to the United States Transuranium and Uranium Registries. The concentration of 239Pu ranged from 0.22 to 15.8 ng/kg. The 240Pu/239Pu isotopic ratios ranged from 0.026 to 0.127 which is consistent with weapons-grade plutonium. Concentration of uranium fell between 1.84 µg/kg and 29.5 µg/kg and 235U/238U ratios ranged from 4.8 × 10-3 to 7.6 × 10-3. Elevated 236U/238U atom ratios were measured in two cases and ranged from 5.0 × 10-6 - 2.4 × 10-5 indicating exposure to spent or reprocessed uranium material. The concentration of 241Am was measured in four hair samples and ranged from 0.02 to 0.21 ng/kg.

Selenium in drinking water and cereal grains, and biomarkers of Se status in urine and fingernails of the Main Ethiopian Rift Valley population.

BACKGROUND: Selenium (Se) plays an important role in human health, yet Se overexposure or deficiency can lead to deleterious health effects. This study aims to determine the concentration of Se in drinking water and staple cereal grain (maize, wheat, and teff) samples from the Main Ethiopian Rift (MER) Valley, and correspondingly, assesses Se biomarkers and their status as measured in the urine and fingernails of 230 individuals living in 25 MER communities. METHOD: The concentration of Se in drinking water and cereal grain (maize, wheat, and teff) samples, and urine and fingernail samples were measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Demographic, anthropometric, and elemental concentrations were described by their quartiles and mean ± standard deviations. The 5th and 95th percentiles were used to describe the concentrations Se biomarkers ranges. The Se biomarker distributions in different study communities were further characterized according to Se levels found in drinking water, sex, and age using ANOVA, and multivariate regression. We conducted a correlation analysis (with Pearson correlation coefficient) and fitted a regression to evaluate the associations between these variables. RESULTS: The mean concentration of Se in the drinking water samples was 0.66 (range: 0.015-2.64 µg/L; n = 25), and all samples were below the threshold value of 10 µg/L for Se in drinking water set by the World Health Organiation (WHO). In Ethiopia, most rural communities rely on locally produced cereal grains. We found mean Se concentrations (µg/kg) of 357 ± 190 (n = 14), 289 ± 123 (n = 14), and 145 ± 100 (n = 14) in wheat, teff, and maize, respectively. Furthermore, Se concentrations in drinking water showed no significant correlation with biomarker measures, indicating that the primary source of dietary Se is likely from local foods including staple grains. The mean±SD (5th-95th percentiles) of Se concentrations in fingernails and urine among study subjects were 1022 ± 320 (624-1551 µg/kg), and 38 ± 30 (1.9-100 µg/L), respectively. CONCLUSION: A sizeable share of study participants (31%) fell below the lower limits of what is considered the currently accepted Se range of 20-90 µg/L in urine, though relatively few (only 4%) had similarly low fingernail levels. On the other hand, none of the samples reached Se toxicity levels, and the biomarker levels in this study are comparable to results from other studies that find adequate Se. Our results show that Se toxicity or deficiency is unlikely in the study population.

Toenail zinc as a biomarker: Relationship with sources of environmental exposure and with genetic variability in MCC-Spain study.

BACKGROUND: Toenails are commonly used as biomarkers of exposure to zinc (Zn), but there is scarce information about their relationship with sources of exposure to Zn. OBJECTIVES: To investigate the main determinants of toenail Zn, including selected sources of environmental exposure to Zn and individual genetic variability in Zn metabolism. METHODS: We determined toenail Zn by inductively coupled plasma mass spectrometry in 3,448 general population controls from the MultiCase-Control study MCC-Spain. We assessed dietary and supplement Zn intake using food frequency questionnaires, residential proximity to Zn-emitting industries and residential topsoil Zn levels through interpolation methods. We constructed a polygenic score of genetic variability based on 81 single nucleotide polymorphisms in genes involved in Zn metabolism. Geometric mean ratios of toenail Zn across categories of each determinant were estimated from multivariate linear regression models on log-transformed toenail Zn. RESULTS: Geometric mean toenail Zn was 104.1 µg/g in men and 100.3 µg/g in women. Geometric mean toenail Zn levels were 7 % lower (95 % confidence interval 1-13 %) in men older than 69 years and those in the upper tertile of fibre intake, and 9 % higher (3-16 %) in smoking men. Women residing within 3 km from Zn-emitting industries had 4 % higher geometric mean toenail Zn levels (0-9 %). Dietary Zn intake and polygenic score were unrelated to toenail Zn. Overall, the available determinants only explained 9.3 % of toenail Zn variability in men and 4.8 % in women. DISCUSSION: Sociodemographic factors, lifestyle, diet, and environmental exposure explained little of the individual variability of toenail Zn in the study population. The available genetic variants related to Zn metabolism were not associated with toenail Zn.

Selenium and cancer risk: Wide-angled Mendelian randomization analysis.

Evidence on the association between selenium and cancer risk is inconclusive. We conducted a Mendelian randomization study to examine the associations of selenium levels with 22 site-specific cancers and any cancer. Single nucleotide polymorphisms (SNPs) strongly associated with toenail and blood (TAB) and blood selenium levels in mild linkage disequilibrium (r2 < .3) were used as instrumental variables. Genetic associations of selenium-associated SNPs with cancer were obtained from the UK Biobank including a total of 59 647 cancer cases and 307 914 controls. Associations with P < .1 in UK Biobank were tested for replication in the FinnGen consortium comprising more than 180 000 individuals. The inverse-variance weighted method accounting for linkage disequilibrium was used to estimate the associations. Genetically predicted TAB selenium levels were not associated with the risk of the 22 site-specific cancers or any cancer (all 22 site-specific cancers). Similarly, we observed no strong association for genetically predicted blood selenium levels. However, genetically predicted blood selenium levels showed suggestive associations with risk of kidney cancer (odds ratio [OR] per one-unit increase in log-transformed levels: 0.83; 95% confidence interval [CI]: 0.67-1.03) and multiple myeloma (OR: 1.40; 95% CI: 1.02-1.93). The same direction of association for kidney cancer but not for multiple myeloma was observed in FinnGen. In the metaanalysis of UK Biobank and FinnGen, the OR of kidney cancer was 0.83 (95% CI: 0.69-1.00). Our study suggests that high selenium status may not prevent cancer development. The associations for kidney cancer and multiple myeloma need to be verified in well-powered studies.

Traces under nails in clinical forensic medicine: not just DNA.

When dealing with complex crimes such as rape and assault, every trace takes on an essential role. The hands are often the only means of defence and offence for the victim as well as a frequent area of contact with the environment; fingernails of a victim are a well-known possible source of DNA of the aggressor; nevertheless, they are more rarely treated as an area of interest for non-genetic material, particularly on living victims. The hyponychium, because of its physiological protective function, lends itself ideally to retaining different kinds of traces representative of an environment or various products and substrates that could shed light on the environment and objects involved in the event. We therefore tested how far this capability of the hyponychium could go by simulating the dynamics of contamination of the nail through scratching on different substrates (brick and mortar, painted wood, ivy leaves, cotton and woollen fabric, soil) and persistence of any contaminant at different time intervals. We have thus shown how these traces may remain in the living for up to 24 h after the event using inexpensive and non-destructive techniques such as the episcopic and optical microscope.

Arsenic and selenium measurements in nail and hair show important relationships to Alzheimer's disease in the elderly.

BACKGROUND AND RESEARCH QUESTION: The relationships of Arsenic (As) and selenium (Se) to Alzheimer's Disease (AD) are not clearly known. This case-control observational study aims to investigate the possible relationship of these elements to the diagnosis and pathophysiology of the disease. METHODS: This case-control observational study was performed using 40 AD patients in different clinical stages and 40 healthy control subjects, living in a similar environment with low As exposure. The levels of As and Se in nail and hair were measured with Inductively Coupled Plasma Mass Spectrometry. The results were analysed with regards to clinical condition, age, disease duration, sex, education, living environment, and the relationship of the two elements using Mann Whitney U test and Spearman Rho or Pearson correlation tests as appropriate. RESULTS: The levels of As and Se were not related to age, disease duration, sex, education, or living environment in the study groups (p > 0.05). The levels of As and Se in hair and nail samples of all patients and patient subgroups were higher than those in the healthy subjects (p < 0.001). A positive correlation was found between the levels of As and Se in both hair and nail samples only in the patient group (p < 0.01). CONCLUSION: According to the results, As and Se levels probably increase due to some metabolic or genetic factors affecting both of them together. There may be an increase in the unregulated pool (selenomethionine) and a decrease in the regulated pool of Se (selenosycteine) in AD. Our findings need verification and the subject seems to deserve more elaborate evaluations including genetic analyses and analysis of different chemical forms of these elements.

Are Obese Patients with Autism Spectrum Disorder More Likely to Be Selenium Deficient? Research Findings on Pre- and Post-Pubertal Children.

Selenium is involved in many metabolic pathways that are critical for life. Information concerning the metabolic effects of selenium in autism spectrum disorder (ASD) and obesity is still conflicting and incomplete. The pre- and post-pubertal selenium profiles of patients with ASD and obesity have not yet been investigated. The goal of the study was to examine selenium content before and after puberty in euthyroid children diagnosed with ASD, compared to age-matched neurotypical controls, with respect to overweight or obesity as a co-existing pathology. Serum, toenail, and 24h urine selenium levels were determined by inductively coupled plasma mass spectrometry in 287 prepubertal children (mean age 8.09 years), divided into groups: ASD with overweight/obesity (ASD+/Ob+); ASD without overweight/obesity (ASD+/Ob-); non-ASD with overweight/obesity (ASD-/Ob+); and non-ASD without overweight/obesity (ASD-/Ob-). The assessment was repeated in 258 of the children after puberty (mean age 14.26 years).The lowest serum (p < 0.001), urine (p < 0.001) and toenail (p < 0.001) selenium levels before and after puberty were observed in ASD+/Ob+ patients, and the highest in ASD-/Ob-. There were no differences in serum/toenail selenium levels between ASD+/Ob- and ASD-/Ob+ groups. The presence of ASD was associatedwith lower serum (p < 0.001) and toenail (p < 0.001) selenium in BMI-matched groups. In neurotypical patients, post-pubertal serum selenium levels were lower (p < 0.001) than pre-pubertal levels. In the multiple linear regression analyses, selenium levels showed inverse relationships with BMI (p < 0.001) and male gender (p < 0.001), irrespective of the sample type. The serum (p = 0.002) and toenail (p < 0.001) selenium levels were inversely associated with the presence of ASD. ASD, obesity/overweight, and male gender have independent impacts on selenium levels in children. Puberty may affect selenium content in neurotypical children of both genders, but not in ASD patients.

Using human hair and nails as biomarkers to assess exposure of potentially harmful elements to populations living near mine waste dumps.

Potentially harmful elements (PHEs) manganese (Mn), cobalt (Co), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) were measured in human hair/nails, staple crops and drinking water to ascertain the level of exposure to dust transference via wind and rain erosion for members of the Mugala community living near a mine waste dump in the Zambian Copperbelt. The mean PHE concentrations of hair in decreasing order were Zn (137 ± 21 mg/kg), Cu (38 ± 7 mg/kg), Mn (16 ± 2 mg/kg), Pb (4.3 ± 1.9 mg/kg), Ni (1.3 ± 0.2 mg/kg) and Cr (1.2 ± 0.2 mg/kg), Co (0.9 ± 0.2 mg/kg) and Cd (0.30 ± 0.02 mg/kg). Whilst for toenails the decreasing order of mean concentrations was Zn (172 ± 27 mg/kg), Cu (30 ± 5 mg/kg), Mn (12 ± 2 mg/kg), Pb (4.8 ± 0.5 mg/kg), Ni (1.7 ± 0.14 mg/kg) and Co (1.0 ± 0.02 mg/kg), Cr (0.6 ± 0.1 mg/kg) and Cd (0.1 ± 0.002 mg/kg). The concentration of these potentially harmful elements (PHEs) varied greatly among different age groups. The results showed that Mn, Co, Pb, Cd and Zn were above the interval values (Biolab in Nutritional and environmental medicine, Hair Mineral Analysis, London, 2012) at 0.2-2.0 mg/kg for Mn, 0.01-0.20 mg/kg for Co, < 2.00 mg/kg for Pb, < 0.10 mg/kg for Cd and 0.2-2.00 mg/kg for Zn, whilst Ni, Cu and Cr concentrations were within the normal range concentrations of < 1.40 mg/kg, 10-100 mg/kg and 0.1-1.5 mg/kg, respectively. Dietary intake of PHEs was assessed from the ingestion of vegetables grown in Mugala village, with estimated PHE intakes expressed on a daily basis calculated for Mn (255), Pb (48), Ni (149) and Cd (33) µg/kg bw/day. For these metals, DI via vegetables was above the proposed limits of the provisional tolerable daily intakes (PTDIs) (WHO in Evaluation of certain food additive and contaminants, Seventy-third report of the Joint FAO/WHO Expert Committee on Food Additives, 2011) for Mn at 70 µg/kg bw/day, Pb at 3 µg/kg bw/day, Ni and Cd 5 µg/kg bw/day and 1 µg/kg bw/day, respectively. The rest of the PHEs listed were within the PTDIs limits. Therefore, Mugala inhabitants are at imminent health risk due to lead, nickel and cadmium ingestion of vegetables and drinking water at this location.

Toenails as biomarker of exposure to essential trace metals: A review.

Health problems associated with essential trace metals can result from both inadequate (i.e., low intake) and excessive exposures (i.e., from environmental and/or occupational source). Thus, measuring the exposure level is a real challenge for epidemiologists. Among non-invasive biomarkers that intend to measure long-term exposure to essential trace metals, the toenail is probably the biological matrix with the greatest potential. This systematic review collects the current evidence regarding the validity of toenail clippings as exposure biomarker for trace metals such as boron, cobalt, copper, iron, manganese, molybdenum, selenium, silicon, vanadium and zinc. Special attention was paid to the time-window of exposure reflected by the toenail, the intraindividual variability in exposure levels over time in this matrix, and the relationship of toenail with other biomarkers, personal characteristics and environmental sources. Our search identified 139 papers, with selenium and zinc being the most studied elements. The variability among studies suggests that toenail levels may reflect different degrees of exposure and probably correspond to exposures occurred 3-12 months before sampling (i.e., for manganese/selenium). Few studies assessed the reproducibility of results over time and, for samples obtained 1-6 years apart, the correlation coefficient were between 0.26 and 0.66. Trace metal levels in toenails did not correlate well with those in the blood and urine and showed low-moderate correlation with those in the hair and fingernails. Available data suggests that for some elements (Se, Mn, Zn) toenail concentrations reflect long-term external exposures in fairly reproducible levels, while for other metals, this association has not yet been assessed. Among dietary factors, only toenail selenium showed clear associations with the intake of supplements or specific foods. The toenail levels could also represent occupational exposure, for instance, Mn exposure in welders. The scarcity of information on other essential trace elements, together with the great heterogeneity among studies makes the validation of the usage of toenails as biomarkers of exposure to these elements difficult. Standardization of sample collection, quality control, analytical techniques and reporting procedures might facilitate further research focused on the clear understanding of the significance of essential levels in this promising matrix and would enhance its utility in epidemiological research.

Blood pressure levels and hypertension prevalence in a high selenium environment: results from a cross-sectional study.

BACKGROUND AND AIMS: Recent human and laboratory studies have suggested the possibility that selenium overexposure may increase blood pressure. We sought to ascertain whether adults living in a seleniferous area exhibit an association between selenium exposure and both blood pressure levels as well as prevalence of hypertension. METHODS AND RESULTS: We measured selenium levels in blood (serum), hair and nail samples obtained from 680 adult volunteers (267 men and 413 women), living in seven Punjabi villages in a seleniferous area and related them to health outcomes, including systolic and diastolic blood pressure and presence of hypertension. In a multivariable restricted cubic spline regression model, adjusted for age, sex and history of hypertension, we found a positive association between systolic blood pressure and both serum (P = 0.004) and hair (P = 0.058) selenium levels, but not with nail selenium content. Little association emerged between the three selenium biomarkers and diastolic blood pressure. Hypertension prevalence was positively associated with the three exposure indicators (P < 0.001). The associations we found were generally stronger in women than in men. CONCLUSIONS: Overall, these findings suggest that chronic overexposure to environmental selenium may increase blood pressure, though there were inconsistencies for this association according to the choice of exposure indicator, the study endpoint and the sex.

Effects of seafood consumption and toenail mercury and selenium levels on cognitive function among American adults: 25 y of follow up.

OBJECTIVES: The aim of this study was to examine the longitudinal association between seafood and intake of long-chain ω-3 polyunsaturated fatty acids (LCω-3 PUFA) and cognitive function and to explore the possible effect modifications owing to mercury (Hg) and selenium (Se) levels. METHODS: Participants (N = 3231) from the CARDIA (Coronary Artery Risk Development in Young Adults) study underwent baseline examination and were reexamined in eight follow-up visits. Diet was assessed at baseline and in exam years 7 and 20. Toenail Hg and Se were measured at exam year 2. Cognitive function was measured at exam year 25 using three tests: Rey Auditory Verbal Learning Test (RAVLT), Digit Symbol Substitution Test (DSST), and the Stroop test. The general linear regression model was used to examine cumulative average intakes of LCω-3 PUFA and seafood in relation to the cognitive test scores; and to explore the possible effect modifications caused by Hg and Se. RESULTS: LCω-3 PUFA intake was significantly associated with better performance in the DSST test (quintile 5 versus quintile 1; mean difference = 1.74; 95% confidence interval, 0.19-3.29; Ptrend, 0.048]), but not in the RAVLT and Stroop tests. Similar results were observed for intakes of eicosapentaenoic acid, docosahexaenoic acid, and non-fried seafood. The observed associations were more pronounced in participants with body mass index ≥25 kg/m2, but not significantly modified by toenail Hg or Se. CONCLUSION: This longitudinal study supported the hypothesis that LCω-3 PUFA or non-fried seafood intake is associated with better cognitive performance in psychomotor speed among US adults, especially those who are overweight or obese.

Association between Serum Selenium Level and the Presence of Diabetes Mellitus: A Meta-Analysis of Observational Studies.

BACKGROUND: Epidemiological studies have suggested an association between selenium (Se) and diabetes mellitus (DM). However, different studies have reported conflicting results. Therefore, we performed a comprehensive meta-analysis to clarify the impact of Se on DM. METHODS: We searched the PubMed database for studies on the association between Se and DM from inception to June 2018. RESULTS: Twenty articles evaluating 47,930 participants were included in the analysis. The meta-analysis found that high levels of Se were significantly associated with the presence of DM (pooled odds ratios [ORs], 1.88; 95% confidence interval [CI], 1.44 to 2.45). However, significant heterogeneity was found (I²=82%). Subgroup analyses were performed based on the Se measurement methods used in each study. A significant association was found between high Se levels and the presence of DM in the studies that used blood (OR, 2.17; 95% CI, 1.60 to 2.93; I²=77%), diet (OR, 1.61; 95% CI, 1.10 to 2.36; I²=0%), and urine (OR, 1.49; 95% CI, 1.02 to 2.17; I²=0%) as samples to estimate Se levels, but not in studies on nails (OR, 1.24; 95% CI, 0.52 to 2.98; I²=91%). Because of significant heterogeneity in the studies with blood, we conducted a sensitivity analysis and tested the publication bias. The results were consistent after adjustment based on the sensitivity analysis as well as the trim and fill analysis for publication bias. CONCLUSION: This meta-analysis demonstrates that high levels of Se are associated with the presence of DM. Further prospective and randomized controlled trials are warranted to elucidate the link better.

The Screening of Nails for Selected Essential and Toxic Elements in Normotensive and Pre-Eclamptic Women.

To compare the concentrations of 13 different elements in nail samples from pre-eclamptic and normotensive pregnant women. The study site was a regional hospital in Durban, KwaZulu Natal. Nail samples were collected from normotensive (n = 33) and pre-eclamptic (n = 33) pregnant women. Approximately 0.02 g of nail samples were digested in 70% nitric acid and analyzed using inductively coupled plasma-optical emission spectrometry. Analytes of interest were the following essential elements calcium (Ca), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), selenium (Se) and Zinc (Zn) as well as toxic elements, arsenic (As), cadmium (Cd) and lead (Pb). The observed concentrations of bioelements (mean, µg/g), Ca: normotensive (N) 3467 ± 197 vs (PE) 2897 ± 190; Mg: (N) 736 ± 61 vs (PE) 695 ± 59, were lower in pre-eclampsia albeit not statistically significant. Similarly, the observed concentrations of bioelements (mean, µg/g), Cd: (N) 3 ± 0.3 vs (PE) 2 ± 0.4; Co: (N) 3 ± 0.3 (PE) not detected; Mn: (N) 7 ± 1 (PE) 4 ± 0.8, were significantly lower in pre-eclampsia (p = 0.004, 0.0001 and 0.022, respectively). Therefore, this study demonstrated significantly lower levels of Cd, Co and Mn in pre-eclampsia which justifies the need for further research on these elements towards the effective management or prevention of pre-eclampsia which could ultimately also aid in establishing its pathogenesis.

Toenail concentrations of zinc, selenium and nickel in patients with chronic recurrent warts: A pilot two-group comparative study.

BACKGROUND: Normal immune functioning requires sufficient levels of trace elements including zinc and selenium, while elements such as nickel can be immunotoxic. AIM: To assess long-term abnormalities in zinc, selenium and nickel levels in patients with chronic recurrent warts. METHODS: Toenail samples were taken from 28 patients with chronic recurrent warts and 30 apparently healthy matching controls were analysed. Toenail concentrations of zinc, selenium and nickel were measured using inductively-coupled plasma-optical emission spectroscopy. RESULTS: Selenium levels were significantly higher in patients than in controls (P = 0.03). Levels of trace elements did not correlate with the number or duration of warts. Toenail nickel levels in all subjects were higher than globally reported values. LIMITATIONS: A small sample size and the absence of regional reference ranges for concentrations of trace elements in toenails. CONCLUSION: Zinc does not seem to be involved in the chronicity of warts, and it is unclear if selenium has a protective role against warts. Our finding of high concentrations of nickel in both patients and controls raises concerns about environmental exposure.

Toenail-Based Metal Concentrations and Young-Onset Breast Cancer.

Several metals have carcinogenic properties, but their associations with breast cancer are not established. We studied cadmium, a metalloestrogen, and 9 other metals-arsenic, cobalt, chromium, copper, mercury, molybdenum, lead, tin, and vanadium--in relation to young-onset breast cancer (diagnosis age <50 years), which tends to be more aggressive than and have a different risk profile from later-onset disease. Recent metal exposure was measured by assessing element concentrations, via inductively coupled plasma mass spectrometry, in toenail clippings of 1,217 disease-discordant sister pairs in the US-based Sister (2003-2009) and Two Sister (2008-2010) studies. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals. After correcting for differential calendar time of sample collection, no statistically significant associations were observed between any metals and breast cancer. Vanadium had the largest odds ratio (for fourth vs. first quartile, odds ratio = 1.54, 95% confidence interval: 0.75, 3.16; P for trend = 0.21). The association between cadmium and young-onset breast cancer was near null, with no evidence of a dose-response relationship (for fourth vs. first quartile, odds ratio = 0.95, 95% confidence interval: 0.64, 1.43; P for trend = 0.64). Positive associations between urinary cadmium concentrations and breast cancer have been reported in case-control studies, but we observed no such association between young-onset breast cancer and toenail concentrations of any assessed metals.

Qualitative and quantitative analysis of human nails to find correlation between nutrients and vitamin D deficiency using LIBS and ICP-AES.

In this work, we analysed human fingernails of people who suffer from vitamin D deficiency using the laser-induced breakdown spectroscopy(LIBS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES)techniques. The measurements have been conducted on 71 nail samples collected randomly from volunteers of different genders and ages ranged between 20 and 50 years. The main aim of this study is to find the correlation between vitamin D deficiency and the intensity of some dominated lines in the LIBS spectra. A LIBS spectrum consists of dominant lines of fifteen elements including calcium, magnesium, sodium, potassium, titanium, iron, chloride, sulphur, copper, chromium, zinc, nitrogen, phosphor, and oxygen. By recording the spectrum in specific ranges and focusing on calcium, magnesium, sodium, and potassium, we found a correlation between the intensity of the potassium (K) lines at (766.5 and 769.9 nm)and vitamin D level in both age groups (20 and 25 years old), with weak correlation for the calcium (Ca), magnesium (Mg), and sodium (Na) lines. To verify the validity of the LIBS results, we analysed the nail samples with ICP, a standard analytical technique. The elements detected with our LIBS technique are in a good agreement with those identified by ICP-AES. From the health and physiological perspectives, the LIBS system, which is used for spectral analysis in this work, is appropriate for diagnostic purposes such as to find the correlation between vitamin D deficiency and potassium content, especially for hypertensive patients who simultaneously take potassium-based medication and vitamin D supplement.

Toenail selenium, genetic variation in selenoenzymes and risk and outcome in glioma.

BACKGROUND: Selenium is an essential trace element obtained through diet that plays a critical role in DNA synthesis and protection from oxidative damage. Selenium intake and polymorphisms in selenoproteins have been linked to the risk of certain cancers though data for glioma are sparse. METHODS: In a case-control study of glioma, we examined the associations of selenium in toenails and genetic variants in the selenoenzyme pathway with the risk of glioma and patient survival. A total of 423 genetic variants in 29 candidate genes in the selenoenzyme pathway were studied in 1547 glioma cases and 1014 healthy controls. Genetic associations were also examined in the UK Biobank cohort comprised of 313,868 persons with 322 incident glioma cases. Toenail selenium was measured in a subcohort of 300 glioma cases and 300 age-matched controls from the case-control study. RESULTS: None of the 423 variants studied were consistently associated with glioma risk in the case-control and cohort studies. Moreover, toenail selenium in the case-control study had no significant association with glioma risk (p trend = 0.70) or patient survival among 254 patients with high grade tumors (p trend = 0.70). CONCLUSION: The present study offers no support for the hypothesis that selenium plays a role in the onset of glioma or patient outcome.

Feasibility of measuring zinc in human nails using portable x-ray fluorescence.

A variety of adverse health effects have been identified as resulting from zinc deficiency. Zinc supplementation may therefore be indicated for certain individuals or populations. A rapid and straightforward means of assessing zinc status in humans would be of considerable medical benefit. In this study, the feasibility of measuring zinc levels in human fingernails or toenails using a portable x-ray fluorescence technique was assessed. Whole nail models (or phantoms) were constructed from resin, and dosed with various concentrations of zinc. These different concentration "nails" were cut into small slices of 4.4 ±â€¯0.2 mm width. The combination of these various slices into different arrangements allowed the modeling of different time-dependent zinc exposure scenarios. A portable x-ray fluorescence device was tested using an "open beam" configuration having a beam diameter of ∼9 mm, and using a "weld mask" configuration with the beam width reduced to 2.9 mm. Minimum detection limits were determined to be 0.15 ±â€¯0.01 ppm for the open beam, and 1.13 ±â€¯0.08 ppm when using the weld mask. By scanning across the length of the model nails, it was demonstrated that differences in zinc levels deposited over time could be detected, and that the weld mask configuration was better suited to resolving spatial changes. The x-ray fluorescence approach was found to be highly sensitive for detecting zinc in nail, and capable of differentiating patterns of zinc uptake over time.