A prospective study of selenium status and breast cancer risk.

Low dietary intake of selenium has been proposed as a risk factor for breast cancer. To address this hypothesis, we collected toenail clippings from 62,641 women in the Nurses' Health Study cohort who were free from cancer (other than nonmelanoma skin cancer) in 1982 and 1983. The selenium concentration in nails has been shown to reflect dietary intake of selenium. During 53 months of follow-up, 434 cases of breast cancer were diagnosed among women who had submitted a set of toenail clippings, and we matched one control free from breast and other cancers to each case. The mean selenium level in toenails in the cases (0.823 microgram/g; SD, 0.197) was almost identical to that of the controls (0.821 microgram/g; SD, 0.174). After controlling for known breast cancer risk factors, the relative risk for women in the highest quintile of selenium as compared with the lowest quintile was 1.10 (95% confidence interval, 0.70 to 1.72) and there was no trend across quintiles. Results were similar for both premenopausal and postmenopausal women. Although these data do not exclude a possible influence of selenium intake before adulthood on subsequent risk of breast cancer, selenium intake later in life is not likely to be an important factor in the etiology of breast cancer.

Predictors of selenium concentration in human toenails.

To assess the validity of the selenium concentration in human toenails as a measure of selenium intake and to determine other correlates of toenail selenium level, the authors examined the predictors of toenail selenium within two subgroups of a large cohort study of US women. Mean toenail selenium was higher among 38 consumers of selenium supplements (0.904 micrograms/g, standard deviation (SD) 0.217) than among 96 nonusers (0.748 micrograms/g, SD 0.149; p less than 0.001), and a dose-response relation was observed among supplement users (Spearman's r = 0.32; p = 0.05). In a second subgroup of 677 women, selenium supplement use was also associated with higher mean toenail selenium (0.906 micrograms/g, SD 0.214, among 18 users and 0.801 micrograms/g, SD 0.148, among 659 nonusers; p = 0.02), and the dose-response relation was also significant (Spearman's r = 0.50; p = 0.03). The geographic variation in toenail selenium levels was consistent with the geographic distribution of selenium in forage crops. Toenail selenium declined with age and was significantly reduced among cigarette smokers (mean = 0.746, SD 0.124, among 146 current smokers and mean = 0.817, SD 0.159, among 311 never smokers; p less than 0.001) but was not materially affected by alcohol consumption. A dietary selenium score calculated from a food frequency questionnaire failed to predict toenail selenium level, demonstrating the suspected inability of diet questionnaires to measure individual selenium intake because of the highly variable selenium composition of different samples of the same food.(ABSTRACT TRUNCATED AT 250 WORDS)

Selenium in diet, blood, and toenails in relation to breast cancer: a case-control study.

The association between breast cancer and selenium, measured in the diet, plasma, erythrocytes, and toenails, was investigated in a case-control study in the Netherlands during 1985-1987. Dietary selenium intake was assessed by a structured dietary history technique among 133 breast cancer cases and 238 population controls. Absolute and energy-adjusted selenium intake and selenium concentrations in plasma, erythrocytes, and toenails were similar in cases and controls. The multivariate adjusted odds ratios of breast cancer for subjects in the lowest quartile compared with the highest quartile were 1.6 (95% confidence interval (CI) 0.8-3.4) for dietary selenium, 2.0 (95% CI 0.9-4.4) for plasma selenium, 0.9 (95% CI 0.4-1.9) for erythrocyte selenium, and 1.1 (95% CI 0.6-2.1) for toenail selenium. No statistically significant trend was observed in the odds ratios for any of the four indicators of selenium. These results do not suggest a substantial association between selenium and breast cancer for both short- and long-term markers of selenium status.

Fluoride in the urine, hair, and nails of phosphate fertiliser workers.

The fluoride content in the urine, hair, and nails of 106 workers employed in a phosphate fertiliser plant was significantly raised above the control level. Positive correlations were found between the group means for concentrations of fluorides in urine and hair (r = 0.77), urine and nails (r = 0.99), and hair and nails (r = 0.70). Individual values in the whole population gave significant correlations between concentrations in urine and nails (r = 0.73). The obtained results indicate that the fluoride content in hair and nails may be used as an indicator of occupational exposure to fluorides.

The nutritional selenium status of healthy Greeks.

The nutritional selenium status of apparently healthy Greeks has been assessed by measuring fluorimetrically the selenium content of whole blood, morning urine, hair and finger nails. The means and standard deviations were 165 +/- 33, 25 +/- 7 ng Se ml-1, 416 +/- 86, and 536 +/- 91 ng Se g-1, respectively. No significant difference was found between the selenium content of whole blood, hair and finger nails, but, for morning urine, there was a significant difference between males and females. The young and the elderly have less selenium in these biological materials than other Greeks. Whole blood selenium correlates significantly with morning urine, hair, and finger nail selenium, as does hair and nail selenium of male, female and male + female Greeks. The results are compared with those in the literature and possible explanations for the observations are presented. It is concluded that the selenium status of Greeks is satisfactory.

Cholesterol sulphate levels in the hair and nails of patients with recessive X-linked ichthyosis.

Cholesterol sulphate (CS) has been suggested as an intercellular glue for corneocyte-corneocyte cohesion from studies on patients with recessive X-linked ichthyosis (RXLI). Pathological stratum corneum of RXLI patients was found to show a significant elevation of CS. In the present study hair and nails, unaffected keratinized tissues in RXLI patients, were examined for CS levels. The results demonstrated significantly elevated CS levels in both tissues in RXLI patients (P less than 0.001). In particular the mean CS level in the hair of RXLI patients was five times greater than normal. The present study suggests that hair is a useful material for the diagnosis of RXLI.

Comparison of human hair and nail low-sulfur protein compositions on two-dimensional electrophoresis.

Compositions of human normal hair and nail low-sulfur proteins were compared using two-dimensional electrophoresis of their S-carboxymethylated (SCM) derivatives. Six SCM low-sulfur protein components with molecular weights (MWs) of 76,000, 73,000, 72,000, 64,000, 61,000 and 55,000 were common to the hair and nail. One component with a MW of 61,000 was specific to hair, and two components, both with a MW of 50,000, were specific to nail.

Comparison of hair with nail as index media for biological monitoring of mercury.

Mercury in hair and nails was determined with speciation of chemical forms of mercury. Scalp hair and toenails were sampled once and fingernails were sampled three times from the subjects (18 males and 5 females) whose age ranged from 23 to 56 yr. Total mercury (THg) and inorganic mercury (IHg) were determined by Magos' method with modifications. No sex-related differences were found in mercury levels in hair and nails. In the fingernail samples of three different formation periods, THg and IHg concentrations remained almost constant. Among the three kinds of index media, the highest THg concentration was found in scalp hair followed by fingernails and toenails in the order given, whereas IHg concentrations in scalp hair were similar as those in fingernails but were lowest in toenails. The percent inorganic to total mercury was higher in fingernails than in hair and toenails, which is likely to reflect a possible external contamination with IHg in fingernails. The higher THg concentration in scalp hair than in nails may be attributable to the difference in the chemical composition, in particular sulphur content, and in the blood flow during the formation of hair and nails.

Analysis of methamphetamine in hair, nail, sweat, and saliva by mass fragmentography.

A method for the detection and quantitation of methamphetamine and its major metabolite in hair, nails, sweat, and saliva from habitual users of methamphetamine by mass fragmentography has been developed. Hair and nail samples were washed with water and methanol to remove the external contamination, processed with 0.6M HCl, alkalinized, and extracted with CHCl3/isopropanol (3:1 v/v). Sweat and saliva samples were extracted with methanol. After trifluoroacetyl derivatization, the samples were analyzed by mass fragmentography. Methamphetamine and its major metabolite, amphetamine, were detected in hair, nail, and sweat samples, but methamphetamine alone was detected in saliva samples.

Glycosylated proteins of skin, nail and hair: application as an index for long-term control of diabetes mellitus.

The purpose of the present study was to compare the degrees of nonenzymatically glycosylated proteins in the skin (stratum corneum), the nail, the hair, and hemoglobin obtained simultaneously from the same subject and to evaluate the most useful sample for management of diabetic complications. Fifty-one diabetic patients and 20 control patients were examined, utilizing furosine determination. Furosine value of the skin in diabetics was 2.14 +/- 1.70%, whereas that in controls was 1.65 +/- 0.47%. Furosine value of the nail in diabetics was 6.67 +/- 3.30%, whereas that in controls was 4.16 +/- 1.62%. Furosine value of the hair in diabetics was 1.30 +/- 1.11%, whereas that in controls was 1.29 +/- 1.71%. Close correlations were detected between HbA1 (glycosylated hemoglobin) and furosine of the nail (r = 0.58, p less than 0.001), HbA1 and furosine of the skin (r = 0.48, p less than 0.001), and HbA1 and furosine of the hair (r = 0.43, p less than 0.01); however, poor correlations were found between furosine of the hair and the skin (r = 0.35, p less than 0.05) and furosine of the nail and the hair (r = 0.33, p less than 0.05). Furosine of the nail was significantly correlated with the FBS (fasting blood sugar) of the same time, previous 6, and previous 12 months. Furosine value of the nail, we believe, is the most useful indicator for evaluating long term control of diabetics and may provide useful information for management of diabetic complications.

Quantitative trace element analysis of human nails with external beam PIXE.

External beam PIXE (Particle Induced X-ray Emission) analysis with a proton beam of 2.4 MeV was used to study trace element concentrations in human nails. The suitability of PIXE analysis regarding nail samples without any pretreatment besides washing was investigated. The main emphasis has been on the ability to obtain absolute concentration values and a new accurate method for nail sample standardization has been developed. Concentration values for the elements Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, and Pb were determined from human nail samples. A comparison was made with nail samples taken from different fingers and toes to monitor intraindividual variation, and nails of different healthy individuals to get a view of the interindividual differences. The concentrations were also measured in relation to time in order to observe any possible short-term changes. The results are compared with the previous studies reported in the literature. The nail analysis is also compared to hair analysis in terms of detection limits, number of elements determinable, and standardization of the results.

Decreased selenium levels in acute myocardial infarction.

To study the association between selenium status and the risk of myocardial infarction, we compared plasma, erythrocyte, and toenail selenium levels and the activity of erythrocyte glutathione peroxidase among 84 patients with acute myocardial infarction and 84 population controls. Mean concentrations of all selenium measurements were lower in cases than controls. The differences were statistically significant, except for the plasma selenium level. A positive trend in the risk of acute myocardial infarction from high to low toenail selenium levels was observed, which persisted after adjustment for other risk factors for myocardial infarction. In contrast, erythrocyte glutathione peroxidase activity was significantly higher in cases than controls (31.3 +/- 8.4 U/g of hemoglobin and 28.0 +/- 8.1 U/g of hemoglobin, respectively). Because the toenail selenium level reflects blood levels up to one year before sampling, these findings suggest that a low selenium status was present before the infarction and, thus, may be of etiologic relevance. The higher glutathione peroxidase activity in the cases may be interpreted as a defense against increased oxidant stress either preceding or following the acute event.

Human scalp hair as evidence of individual dosage history of haloperidol: method and retrospective study.

Hair samples and morning pre-dose plasma were collected from 40 patients who had received fixed daily doses of haloperidol for more than four months and whose compliance was good. After washing, 1 to 2 cm-long portions nearest to the roots of 2 to 3 strands of hair were completely dissolved in 2.5N NaOH. Haloperidol in that sample or alkalinised plasma was extracted and measured by RIA. Haloperidol concentrations in hair correlated well both with the trough concentration in plasma at steady-state (r = 0.772, n = 39) and with the daily dose (r = 0.555, n = 40). Another keratinized tissue, nail, was also collected from 20 of the 40 patients and the haloperidol level was compared with that in hair. The former was only about 4.3% of the latter and was significantly correlated only with the daily dose (r = 0.525, n = 20). Hair from 10 other patients in whom the dosage of haloperidol had been changed within a few months prior to sampling the hair was cut into 0.5 or 1 cm-long portions from the roots and the drug concentration in each portion was measured. If hairs were assumed to grow at 1 cm/month, a history of individual dosage could be deduced in 9 of the 10 patients from the distribution of drug level along the length of the hair. The results suggest that human scalp hair could serve as a useful tool for monitoring individual dosage history over several months, or in demonstrating exposure or non-exposure of a patient to a drug.

[New toxicokinetic exposure tests for metals based on atomic absorption analysis of the nails]. / Novi toksikokinetichni ekspozitsionni testove za metali na osnovata na atomnoabsorbtsionnoto im opredeliane v nokti.

The up-to-date methodology development for analysis of microelements permits the determination of many of them in small nail samples. The nails of the feet are chosen as biological bioptic material offering some advantages: stability in preserving; higher levels of most toxic elements (in comparison with the levels in serum, blood and urine); a lower rate of surface pollution (in comparison with the hair and nails of the hands); receiving information on the average level of exposure for a long period of time. For the purpose of using nails from the feet in biological control are developed direct AAC - procedures for defining As, A1, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Zn, Mo, Sb and Sn on the basis setting the samples in solution with tetra-alkylammonium hydroxide. The levels of these elements are determined in unexposed persons. The analysis of nails from feet of workers exposed to Pb, Cr and Mn proves, statistically, that the level of these metals gives valuable information on the rate of exposure (the quantity entered into the organism) of groups and individuals. This analysis permits longitudinal control on Pb, Cr and Mn - status of the organism by painless sampling, accessible and reliable analytical procedure.

Utilization and requirement of dietary protein taking into account the dermal and miscellaneous nitrogen losses in Japanese women.

Utilization and requirement of mixed protein in the conventional Japanese diet and the obligatory integumental and miscellaneous nitrogen losses were measured in female subjects. Twelve female students aged 18 to 24 years were given conventional low-protein diets at N intake levels of 50, 70, and 90 mg/kg/day for 10 days. Constituents of the diets corresponded to those of average intake of the Japanese in recent years (1982). N balances were estimated and regression equations between N intake (X) and N balance (Y) were calculated by the multiple level-constant variation method. The equation was Y = 0.426X - 40.0 (n = 36, r = 0.615, p less than 0.01) and the intersection of the regression line with zero nitrogen balance was 93.9 +/- 14.3 mg N/kg/day. The mean digestibility was 92.2 +/- 4.7%. In another experimental group, nitrogen losses due to hair, nails, and menstruation in ten Japanese women were 0.624 +/- 0.172, 0.020 +/- 0.005, and 1.76 +/- 0.68 mg/kg/day, respectively. In a third experimental group, mean of the integumental N losses was 2.8 mg/kg/day in both the subjects given a low-protein diet (19 women) and an ordinary-protein diet (4 women). It increased to 12.7 mg N/kg/day when subjects exercised in summer (4 subjects). The protein requirement in the conventional Japanese diet estimated as the sum of the mean requirement of dietary protein and obligatory dermal and miscellaneous nitrogen losses in Japanese women was 99.1 mg N/kg/day or 0.62 g protein/kg/day. The net protein utilization (NPU) of the proteins at the N intake level for N equilibrium was estimated as 48.

Trace element content in fingernails and hair of a nonindustrialized US control population.

The concentrations of 17 elements in the nail and hair of 117 subjects from a nonindustrialized environment were determined by instrumental neutron activation analysis (INAA). A new method of statistical treatment that allows for more meaningful use of detection limit values was used to process the concentration data. Geometric means and standard errors are presented for each element, along with a summary of the effects of age, sex, and treatment on the concentration of each element. For nails, these data represent the first comprehensive study for several important elements. Correlations for each element between hair and nail were determined. With few exceptions, concentrations of nonessential trace elements were positively correlated in hair and nail, whereas concentrations of essential elements showed no correlations. The factors affecting concentrations and control levels must be considered in studying alterations in disease states.

X-ray microanalysis of the fingernails in term and preterm infants.

The element content of the fingernails of 10 term and 14 preterm infants, clipped for the first time after delivery, was determined by x-ray microanalysis. The results showed a decrease in sulfur and aluminum, and a higher chlorine content in term infants in comparison with preterm ones, the difference being statistically significant. Sodium, potassium, calcium, and zinc content did not differ in the two groups. Copper, iron, magnesium, aluminum, and phosphorus were detected in trace amounts only. Cobalt was not detected in the fingernails of newborns in either group. The elevated content of aluminum in the fingernails of preterm infants may be a clue to the osteopenia observed in these infants.