Selenium and exposure to fibrogenic mineral dust: a mini-review.

Individuals exposed to fibrogenic mineral dust may exhibit an impaired antioxidant system and produce high levels of reactive oxygen and nitrogen species through immune cells, contributing to the perturbation of immune cell function, inflammation, fibrosis and lung cancer. The lung diseases which are caused by inhalation of fibrogenic mineral dust, known as pneumoconioses, develop progressively and irreversibly over decades. At the moment there is no known cure. The trace element selenium has potent antioxidant and anti-inflammatory properties mediated mainly through selenoproteins. Research has demonstrated that selenium has the ability to protect against cardiovascular diseases; to kill cancer cells in vitro and reduce cancer incidence; and to immunomodulate various cellular signaling pathways. For these reasons, selenium has been proposed as a promising therapeutic agent in oxidative stress associated pathology that in theory would be beneficial for the prevention or treatment of pneumoconioses such as silicosis, asbestosis, and coal worker's pneumoconiosis. However, studies regarding selenium and occupational lung diseases are rare. The purpose of this study is to conduct a mini-review regarding the relationship between selenium and exposure to fibrogenic mineral dust with emphasis on epidemiological studies. We carried out a systematic literature search of English published studies on selenium and exposure to fibrogenic mineral dust. We found four epidemiological studies. Reviewed studies show that selenium is lower in individuals exposed to fibrogenic mineral dust. However, three out of the four reviewed studies could not confirm cause-and-effect relationships between low selenium status and exposure to fibrogenic mineral dust. This mini-review underscores the need for large follow-up and mechanistic studies for selenium to further elucidate its therapeutic effects.

Serum selenium and selenoprotein P in patients with silicosis.

OBJECTIVES: Selenoprotein P (SeP) is a selenium (Se) supply protein, which is an antioxidant micronutrient considered to be vital for human health. The aim of this study was to assess the serum selenium status in patients with silicosis. METHODS: We conducted a retrospective case-control study where serum samples from a total of 78 patients (males with a median age of 73.5 years old) with silicosis and 20 healthy controls (males with a median age of 72.5 years old) were assayed for Se and SeP. They underwent medical and job history taking, lung function testing, and chest radiography examinations. Levels of serum Se were measured using electrothermal atomic absorption spectrophotomerty, while levels of SeP were assessed with sandwich Enzyme Immunoassay. Spearman's rank correlation test was carried out to evaluate the relationship between Se and SeP. The Mann-Whitney test was used to evaluate differences in serum Se and SeP between study groups. RESULTS: The median serum Se and SeP concentrations were significantly lower in cases (74.0 µg/l and 4.2mg/l, respectively) compared with controls (116.0 µg/l and 5.8 mg/l, respectively). In both cases and controls, serum Se was positively correlated with serum SeP (rho=0.781, p<0.001 and rho=0.768, p<0.001, respectively). Serum Se and SeP levels were significantly lower in patients classified in category four compared with those who were classified in category two or three. CONCLUSIONS: Serum Se and SeP concentrations were found to be at inadequate levels in patients with silicosis, and decreased significantly with the severity of the disease.

Direct analysis of powder samples using transversely excited atmospheric CO2 laser-induced gas plasma at 1 atm.

A novel method for the direct and sensitive analysis of powder samples has been developed by utilizing the characteristics of a transversely excited atmospheric (TEA) CO(2) laser. In this study, a powder sample was placed in a container and covered by a metal mesh; the metal mesh functions to control the blowing-off of the powder. The container was then perpendicularly attached on a metal surface. When a TEA CO(2) laser (1.5 J, 200 ns) was focused on the metal surface, a large hemispherical gas plasma (radius of around 8 mm) with long emission lifetime (several tens of microseconds) was produced without ablating the metal surface. The high-speed expansion force of the gas plasma samples the powder covered by the metal mesh and fine powder particles are sent into the gas plasma region to be dissociated and excited. Sensitive semi-quantitative analysis was made on organic powder samples such as powdered rice, starch, seaweed (agar), and supplements. The detection limit of heavy metals of Cr in powdered mineral supplement was approximately 0.55 mg/kg.

Differences in associations between markers of antioxidative defense and asthma are sex specific.

BACKGROUND: Lungs are exposed to high levels of oxygen, air pollutants, and smoke, all of which stimulate the production of reactive oxygen species (ROS). In addition, inflammatory cells produce ROS, and thus there may be increased demand for antioxidants, including antioxidant enzymes, in inflammatory lung diseases such as asthma. Sex-specific differences have been noted for asthma, which in postpubertal subjects is predominantly found in females. These sex-specific differences may be associated with differences on the molecular level as well. OBJECTIVE: The aim of this cross-sectional study was to examine associations between markers of antioxidative defense and asthma, and to investigate whether these associations were different between women and men. METHODS: Based on the European Community Respiratory Health Survey protocol, subjects were enrolled in a study of asthma risk factors. The multicenter study was conducted in 5 west Danish counties between 2003 and 2006, and the subjects were recruited as a case-enriched random sample of 10,000 Danish inhabitants aged 20 to 44 years selected by their civil registration number. Participants were identified by positive answers to asthma questions on a screening questionnaire, random sampling, or both. Serum selenium concentrations and antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase [GPX], glutathione reductase [GR], and glucose-6-phosphate dehydrogenase [G6PD]) in erythrocytes were measured. Asthma was defined as either current asthma symptoms with bronchial hyperresponsiveness (BHR) or a continuous asthma score based on 8 questions. RESULTS: A total of 1191 mostly white women and men (mean [SD] age, 34.0 [7.1] and 35.1 [7.1] years, respectively) were enrolled in the study. Current asthma symptoms were present in 29.9% (200/670) of women and 22.5% (117/521) of men, with women reporting more positive answers (51.1% vs 40.9%, respectively; P < 0.01) to asthma questions. Serum selenium concentrations were measured in 1151 subjects (640 women, 511 men), and antioxidant enzyme activities were measured in 295 subjects (161 women, 134 men). Women had higher enzyme activities of most antioxidant enzymes (GPX, P = 0.006; GR, P < 0.001; and G6PD, P = 0.009) than did men. Although the serum selenium concentration was inversely associated with asthma in both sexes, there was a female preponderance, with 3.5% lower serum selenium in subjects with current asthma symptoms with BHR (n = 77) compared with controls (n = 287). GR activity was associated with asthma in men, with 5.7% higher enzyme activity in subjects with current asthma symptoms with BHR (n = 14) compared with controls (n = 77). However, a significant interaction with gender was observed for analyses of GR (P = 0.02), but not for analyses of selenium. CONCLUSIONS: In this study of asthma risk factors, women had higher levels of enzyme activities than did men in a randomly selected Danish population, and sex-specific differences were found in the associations between markers of antioxidative defense and asthma.

Sex determines the influence of smoking and gene polymorphism on glutathione peroxidase activity in erythrocytes.

OBJECTIVE: Glutathione peroxidase 1 (GPX1) is one of the major oxidative enzymes. Our aim was to characterize factors influencing its activity and to determine whether or not the activity is associated with asthma. MATERIAL AND METHODS: Serum selenium concentration was measured, GPX1 polymorphisms were genotyped and smoking history was obtained in a Danish population-derived case-base cohort of 1,191 subjects designed to evaluate risk factors for asthma. GPX1 activity was measured in 134 male and 164 female subjects equally distributed according to genotype of GPX1. Among these subjects, 82 (28 %) had doctor-diagnosed asthma. RESULTS: The average serum selenium concentration was too low for optimal enzyme activity (mean (SE), 83.4 (0.76) ng/mL). GPX1 activity in men was lower than in women, 52.6 (0.66) and 56.4 (0.59) U/g protein, respectively (p<0.001). In men, activity was positively associated with serum selenium concentration (p = 0.005) and negatively associated with both active smoking (p = 0.009) and exposure to environmental tobacco smoke (p = 0.02). In women, activity was associated with genotypes with 59.2 (1.4), 56.0 (1.4) and 54.2 (1.4) U/g protein in the homozygote wild-type, the heterozygote and the homozygote variant type, respectively (p = 0.001). Doctor-diagnosed asthma was unrelated to GPX1 activity in either sex. CONCLUSION: Determinants for activity in the oxidative enzyme GPX1 show marked differences between the sexes, but the activity is not associated with asthma. Sex ought to be taken into consideration when analysing the activity of the enzyme.

New technique for the direct analysis of food powders confined in a small hole using transversely excited atmospheric CO(2) laser-induced gas plasma.

Taking advantage of the differences between the interactions of transversely excited atmospheric (TEA) CO(2) lasers with metal and with organic powder, a new technique for the direct analysis of food powder samples has been developed. In this technique, the powder samples were placed into a small hole with a diameter of 2 mm and a depth of 3 mm and covered by a metal mesh. The TEA CO(2) laser (1500 mJ, 200 ns) was focused on the powder sample surfaces, passing through the metal mesh, at atmospheric pressure in nitrogen gas. It is hypothesized that the small hole functions to confine the powder particles and suppresses the blowing-off of sample, while the metal mesh works as the source of electrons to initiate the strong gas breakdown plasma. The confined powder particles are then ablated by laser irradiation and the ablated particles move into the strong gas breakdown plasma region to be atomized and excited; this method cannot be applied for the case of Nd:YAG lasers because in such case the metal mesh itself was ablated by the laser irradiation. A quantitative analysis of a milk powder sample containing different concentrations of Ca was successfully demonstrated, resulting in a good linear calibration curve with high precision.

[Mortality, causes and places of death among the elderly with dementia in a community: results of a ten-year follow-up study].

OBJECTIVES: The study was conducted to analyze risk, causes and places of death, and related factors among elderly with and without dementia in a community. METHODS: In 1994, the entire elderly population, aged 65 and older in city K were surveyed for their health status. Among them, 201 were diagnosed as suffering from dementia by psychiatric doctors, according to DSM-III-R. Date, causes and places of death were surveyed individually using the vital statistics record of the national government, for ten years from July 1, 1994. The risk of death adjusted for age-classes, was analyzed with the Cox proportional hazard model. Median survival time was calculated using the Kaplan-Maier method, and causes and places of death were analyzed with the chi2 test. Ten factors at the baseline study were examined for each sex, to analyze their relations to death. RESULTS: Among 198 elderly with dementia followed, 170 died (85.9%), while 1696 (33.9%) died in the 5004 non-dementia group. The hazard ratio for dementia/non-dementia was 2.99, and the female/male was 0.56, stratified by age-classes. The rate for death due to CVD in the elderly with dementia was particularly high accounting for 37.1% of the total. With the CVD and undifferentiated types of dementia, the rate was 47.0%. The rate for malignant tumor was low. In the dementia group, mortality at nursing homes was higher and at hospitals/clinics was lower, compared to non-dementia group (p< 0.05). When stratified by age-classes, the factors significantly related to death of the elderly with dementia were severity of dementia (male), type of dementia (female), being bed-ridden and having impaired walking or toileting capabilities (both sexes). CONCLUSIONS: Dementia is a significant death related factor for elderly people, particularly linked to mortality from cerebro-vascular disease. The type and severity of dementia, and walking or toileting activities appear significant to be factors for death of elderly with dementia.

[Prevalence of intimate partner violence and related factors in a local city in Japan].

OBJECTIVES: This study sought to assess the prevalence of intimate partner violence in a local city of Fukui Prefecture, and whether the subjects' and their partners' demographic characteristics, alcohol use, and violence experienced in the families in which they were raised might be related risk factors. METHODS: We conducted a mail survey of 1,000 subjects aged 20-69 in the city randomly sampled from the population of 45,220 that were stratified by 10 years of age and sex and pulled 100 from each group. Data from two 248 respondents were eligible for analysis. The self-administered questionnaire included items on; 1) whether they were the victims of physical, sexual, social-economic and psychological violence from their intimate partners, and whether they perpetrated violence or not on their partners; 2) demographic characteristics of the subjects and their partners with information on gender, age, occupation, educational background, annual income, the cohabitants, and their alcohol use; 3) the subjects' experience of violence in the family in which they had grown up; exposure to violence between their parents, and being abused by them. RESULTS: Out of 248 subjects, men accounted for 41.5%. The prevalence rate of any violence experienced from intimate partners was 46.4%, and that of having perpetrated any violence on the partner was 43.1%. Women reported experiencing more "sexual violence" from their partners than did men. In addition, men admitted to more "physical, sexual, and psychological violence" on their partners than women. Those who had themselves been exposed to violence between parents or were victimized by their parents significantly had more experience of violence from their partners and perpetration than those who did not. CONCLUSION: The results suggest that questioning about the experience of violence in the family is useful for the early detection of intimate partner violence.

Occupational allergy in medical doctors.

Allergic diseases have increased in many developed countries including Japan. Doctors are also at risk for allergic diseases from exposure to allergens in working conditions and hospital environments. We investigated the factors relating to occupational allergy in doctors. Self-administered questionnaires were mailed to all doctors (n=895) who had previously graduated from School of Medicine, Fukui Medical University. Data from 307 responders (response rate: 34.3%, male 241, female 66, mean age +/- S.D., 30.8 +/- 4.2) were analyzed. Eighty-nine doctors stated that they had occupational allergy including contact dermatitis, allergic rhinitis and/or asthma. Fifty-four had contact dermatitis caused by surgical gloves; 77 had contact dermatitis from disinfectants, e.g. 23 from chlorhexidine gluconate; 21 from povidone iodine; and 15 from ethanol. Fifteen doctors experienced allergic rhinitis and/or asthma caused by handling laboratory animals. Univariate analysis showed that profession (surgical doctors) and past histories of allergic diseases (rhinitis, sinusitis, or atopic dermatitis) were significantly related to occupational allergy in doctors, but that gender, smoking or physical exercise were not significantly related to it. A logistic regression analysis showed that past histories of allergic diseases and the profession of surgical doctors were significantly related to occupational allergy, but that gender, age or smoking were not significantly related to it. The results of the present study suggest that past history of allergic diseases is a factor predisposing to occupational allergy in doctors. It is necessary and possible to extend more prophylactic measures for doctors, especially for surgeons, because exposure to responsible agents and materials for them can be more frequent.

Selenium serum and urine is associated to mild asthma and atopy. The SUS study.

To examine the associations between selenium (Se) status, asthma, bronchial hyperresponsiveness (BHR), and atopy in 154 male subjects (72 with mild asthma, 41 with BHR and 41 with no respiratory symptoms) aged 18 (range 17-22) years. Each subject underwent a medical interview and FEV1 and FVC were recorded. Histamine bronchial reactivity (Yan method) was measured, skin prick test (inhalant allergens) was performed and Se in urine and serum was analysed (AOAC modified fluometric method). Se in serum 74.04 (10.58) micrograms/L (mean (SD)) was lower in subjects with asthma and the logarithm of the ratio of Se in serum (microgram/L) and urine standardised to creatinine excretion (ng/mg creatinine) 0.748 (0.096) (mean (SD)) was lower in subjects with asthma and atopy compared to subjects with no allergic symptoms 77.79 (10.16) micrograms/L and 0.808 (0.111) respectively (p < 0.05). In subjects with asthma atopy was significantly associated to urine Se 0.24 (0.73) (beta (SE)) (p < 0.05). Subjects with BHR had the same Se status as subjects with no respiratory symptoms and heavy smokers had a lower concentration of Se in serum 73.80 (9.56) micrograms/L than non-smokers 78.16 (10.74) micrograms/L (p < 0.05), Se status was associated to asthma and smoking. Measuring Se in urine might add further information to possible relations between Se status, atopy and asthma.