Clinical features of preeclampsia and hypertensive disorders in pregnancies after different frozen embryo transfer regimens

OBJECTIVES

To compare whether the clinical features of preeclampsia (PE) or gestational hypertension (GH) were different in pregnancies after a frozen embryo transfer (FET), depending on the FET regimen used.

STUDY DESIGN

A retrospective study including 58 pregnancies with PE and 64 pregnancies with GH, all with singleton live births. Pregnancies were stratified according to the presence or absence of a corpus luteum (CL).

MAIN OUTCOME MEASURES

Clinical characteristics of PE and GH, maternal background factors, postpartum hemorrhage (PPH), key perinatal outcomes.

RESULTS

Among PE patients, no difference was found in the clinical characteristics and in the maternal background factors, when comparing women with a CL to women without a CL. PE patients in the group without a CL had a hemorrhage of > 500 mL or > 1000 mL significantly more often than patients with a CL. Multivariable analyses confirmed this risk. Perinatal outcomes were similar. Among GH patients, there was no difference in the clinical features and maternal background factors, when comparing CL cycles to cycles without a CL. The amount of PPH was higher among the patients without a CL, but the frequency of a > 500 mL or > 1000 mL hemorrhage was similar between groups. No risk increase was seen in multivariable analyses.

CONCLUSIONS

Among FET patients with PE, the risk of PPH wasincreased in pregnancies after cycles without a CL, compared to cycles with a CL. The presence or absence of a CL did noteffectthe severity of PE and GH, the duration of pregnancy or blood pressure levels.

Self-Reported Restrictive Eating, Eating Disorders, Menstrual Dysfunction, and Injuries in Athletes Competing at Different Levels and Sports

The purpose of this study was to investigate the prevalence of self-reported restrictive eating, current or past eating disorder, and menstrual dysfunction and their relationships with injuries. Furthermore, we aimed to compare these prevalences and associations between younger (aged 15–24) and older (aged 25–45) athletes, between elite and non-elite athletes, and between athletes competing in lean and non-lean sports. Data were collected using a web-based questionnaire. Participants were 846 female athletes representing 67 different sports. Results showed that 25%, 18%, and 32% of the athletes reported restrictive eating, eating disorders, and menstrual dysfunction, respectively. Higher rates of lean sport athletes compared with non-lean sport athletes reported these symptoms, while no differences were found between elite and non-elite athletes. Younger athletes reported higher rates of menstrual dysfunction and lower lifetime prevalence of eating disorders. Both restrictive eating (OR 1.41, 95% CI 1.02–1.94) and eating disorders (OR 1.89, 95% CI 1.31–2.73) were associated with injuries, while menstrual dysfunction was associated with more missed participation days compared with a regular menstrual cycle (OR 1.79, 95% CI 1.05–3.07). Our findings indicate that eating disorder symptoms and menstrual dysfunction are common problems in athletes that should be managed properly as they are linked to injuries and missed training/competition days.

Factors affecting the sorption of cesium in a nutrient-poor boreal bog

(135)Cs is among the most important radionuclides in the long-term safety assessments of spent nuclear fuel, due to its long half-life of 2.3 My and large inventory in spent nuclear fuel. Batch sorption experiments were conducted to evaluate the sorption behavior of radiocesium ((134)Cs) in the surface moss, peat, gyttja, and clay layers of 7-m-deep profiles taken from a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of radiocesium increased as a function of sampling depth. The highest Kd values, with a geometric mean of 3200 L/kg dry weight (DW), were observed in the bottom clay layer and the lowest in the 0.5-1.0 m peat layer (50 L/kg DW). The maximum sorption in all studied layers was observed at a pH between 7 and 9.5. The in situ Kd values of (133)Cs in surface Sphagnum moss, peat and gyttja samples were one order of magnitude higher than the Kd values obtained using the batch method. The highest in situ Kd values (9040 L/kg DW) were recorded for the surface moss layer. The sterilization of fresh surface moss, peat, gyttja and clay samples decreased the sorption of radiocesium by 38%, although the difference was not statistically significant. However, bacteria belonging to the genera Pseudomonas, Paenibacillus, Rhodococcus and Burkholderia isolated from the bog were found to remove radiocesium from the solution under laboratory conditions. The highest biosorption was observed for Paenibacillus sp. V0-1-LW and Pseudomonas sp. PS-0-L isolates. When isolated bacteria were added to sterilized bog samples, the removal of radiocesium from the solution increased by an average of 50% compared to the removal recorded for pure sterilized peat. Our results demonstrate that the sorption of radiocesium in the bog environment is dependent on pH and the type of the bog layer and that common environmental bacteria prevailing in the bog can remove cesium from the solution phase.

The microbial impact on the sorption behaviour of selenite in an acidic, nutrient-poor boreal bog

(79)Se is among the most important long lived radionuclides in spent nuclear fuel and selenite, SeO3(2-), is its typical form in intermediate redox potential. The sorption behaviour of selenite and the bacterial impact on the selenite sorption in a 7-m-deep profile of a nutrient-poor boreal bog was studied using batch sorption experiments. The batch distribution coefficient (Kd) values of selenite decreased as a function of sampling depth and highest Kd values, 6600 L/kg dry weight (DW), were observed in the surface moss and the lowest in the bottom clay at 1700 L/kg DW. The overall maximum sorption was observed at pH between 3 and 4 and the Kd values were significantly higher in unsterilized compared to sterilized samples. The removal of selenite from solution by Pseudomonas sp., Burkholderia sp., Rhodococcus sp. and Paenibacillus sp. strains isolated from the bog was affected by incubation temperature and time. In addition, the incubation of sterilized surface moss, subsurface peat and gyttja samples with added bacteria effectively removed selenite from the solution and on average 65% of selenite was removed when Pseudomonas sp. or Burkholderia sp. strains were used. Our results demonstrate the important role of bacteria for the removal of selenite from the solution phase in the bog environment, having a high organic matter content and a low pH.

Sorption of radioiodide in an acidic, nutrient-poor boreal bog: insights into the microbial impact

Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ∼ 4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20 °C, and with the bacterial cell counts obtained from plate count agar at +4 °C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH.

Heavy metals in bottom sediments of Lake Umbozero in Murmansk Region, Russia

Sediment cores collected from different locations of Lake Umbozero were studied with respect to concentration and mobility of trace and heavy metals Co, Cu, Fe, Mn, Ni, Pb, U, and Zn. Lake Umbozero is the second largest lake in the Murmansk Region and subjected to contamination by air-borne emissions and river transportation from the nearby metallurgical and mining industries. Unlike its neighboring, more industry-prone Lake Imandra, Lake Umbozero is relatively unexplored with respect to its state of pollution. In our study, metal distribution in sediments was found to vary with respect to the cores, although in general the concentrations were at the same level throughout the lake indicating uniform horizontal distribution of metals. When compared to Lake Imandra, the concentrations of most of the metals studied were significantly lower and represented the levels in sediments measured in lakes of Kola Peninsula located further off from industrial pollutant sources. An exception was Pb the concentration of which was at the same level as in Lake Imandra, probably due to long-distance transport. Sediment layers were subjected to four-step sequential extraction procedure to reveal the metal distribution in soluble, exchangeable, acid-soluble, and residual fractions. Indicative of their potential higher lability, Mn, U, and Zn were generally found in exchangeable fraction; as also Mn and U extensively in the acid-soluble fraction.

Correlation of wood-based components and dewatering properties of waste activated sludge from pulp and paper industry

Large amounts of wet sludge are produced annually in municipal and industrial wastewater treatment. Already in pulp and paper industry, more than ten million tons of primary sludge, waste activated sludge, and de-inking sludge is generated. Waste activated sludge contains large quantities of bound water, which is difficult to dewater. Low water content would be a matter of high calorific value in incineration but it also has effects on the volume and the quality of the matter to be handled in sludge disposal. In this research waste activated sludges from different pulp and paper mills were chemically characterised and dewatered. Correlations of chemical composition and dewatering properties were determined using multivariate analysis. Chemical characterisation included basic sludge analysis, elementary analysis and analysis of wood-based components, such as hemicelluloses and lignin-derived material. Dewatering properties were determined using measurements of dry solids content, flux and flocculant dosage. The effects of different variables varied according to the response concerned. The variables which were significant regarding cake DS increase in filtration or centrifugation and flocculant dosage needed in filtration were different from those which were significant regarding flux.

Soluble and particle-bound 234,238U, 226Ra and 210Po in ground waters

Water of five drilled wells was filtered with three membranes (pore size 0.45 µm-5 kD) to determine the soluble and particle-bound forms of 234,238U, 226Ra and 210Po. Three of the waters were of Ca-HCO3 type and two of Na-Cl type. Some of the waters also exhibited high concentrations of Fe, Mn and humic substances. 234,238U was present entirely in soluble form in all waters, probably as uranyl ion (UO2 2+) in soluble carbonate complexes. 226Ra was in soluble form in the waters with low concentrations of Fe and Mn, but 10% of the total 226Ra activity was bound to particles in the Fe-Mn-rich waters. The behaviour of Po varied with water composition. Particle-bound 210Po was observed to correlate with the combined concentration of iron and manganese in the raw waters. In the two of waters of Na-Cl type, in which the concentrations of Fe, Mn and humic substances were high, salinity of the waters did not enhance the solubility of polonium. Polonium was present in both soluble and particle-bound forms in all the ground waters.

(137)Cs, (239,240)Pu and (241)Am in bottom sediments and surface water of Lake Päijänne, Finland

The concentrations and vertical distribution of (239,240)Pu, (241)Am and (137)Cs in the bottom sediments and water samples of Lake Päijänne were investigated. This lake is important, since the Päijänne area received a significant deposition from the Chernobyl fallout. Furthermore Lake Päijänne is the raw water source for the Helsinki metropolitan area. In addition no previous data on the distribution of plutonium and americium in the sediment profiles of Lake Päijänne exist. Only data covering the surface layer (0-1cm) of the sediments are previously available. In the sediments the average total activities were 45+/-15Bq/m(2) and 20+/-7Bq/m(2) for (239,240)Pu and (241)Am, respectively. The average (241)Am/(239,240)Pu ratio was 0.45+/-0.14. The (241)Am/(239,240)Pu ratio is lowest in the surface layer of the sediments and increases as a function of depth. The (238)Pu/(239,240)Pu ratio of the sediment samples varied between 0.012+/-0.025 and 0.162+/-0.079, decreasing as a function of depth. The average activity in water was 4.9+/-0.9mBq/m(3) and 4.1+/-0.2mBq/m(3) for (239,240)Pu and (241)Am, respectively. The (241)Am/(239,240)Pu ratio of water samples was 0.82+/-0.17. (239,240)Pu originating from the Chernobyl fallout calculated from the average total activities covers approximately 1.95+/-0.01% of the total (239,240)Pu activity in the bottom sediments. The average total (137)Cs activity of sediment profiles was 100+/-15kBq/m(2) and 19.3+/-1.4Bq/m(3) in water samples.

The effect of water treatment on the presence of particle-bound210Po and210Pb in groundwater

The distribution of210Po and210Pb in various particle-size fractions in Finnish groundwater was studied at five private homes. Each site had water treatment equipment comprising either an ion exchange unit or a granular activated carbon filter. Samples of both raw and treated water were filtered using pore sizes ranging from 450 nm to 100 kDa and the activity concentration of210Po and210Pb in the filtrate was determined. In untreated groundwater 86% of210Pb, on average, was found in the large particle fraction (>450 nm). However, in Fe- and Mn-rich water with a high Fe/Mn ratio and in organic-rich water, the majority of210Pb was found in either the intermediate particle (100 kDa–450 nm) or small particle (<100 kDa) fractions. Compared to210Pb,210Po was bound more to the intermediate and small particle fraction. After water treatment,210Pb was found most frequently in the large particle fraction. The size distribution of particle-bound210Po was not as clear as that for210Pb, and in treated water,210Po was more evenly distributed among fractions. The ion exchange unit removed210Pb and210Po bound to the intermediate or small particle fraction, whereas the efficiency of the activated carbon filters in removing210Pb and210Po was independent of the particle size.

Introducing Health Impact Assessment: an analysis of political and administrative intersectoral working methods

BACKGROUND

Intersectoral Action for Health (IAH) and its Health Impact Assessment (HIA) tool are built on collaboration between actors and sectors, requiring multidimensional and horizontal way of working. The study aims to analyse the enablers and barriers when such a new way of working and tool have been initiated to replace a traditional, vertical operation at the local level in Slovakia-a country in transition-in 2004.

METHODS

Up to date, there are few studies that have analysed intersectoral initiatives in relation to politics. In this study the conceptual framework of Kingdon has been used by which the actual problems, the governmental actions (or non-actions) (politics) and the understanding, implementation and evaluation of the initiative (policy) could be analysed. All actors involved, civil servants, politicians, representatives of the local public health institute and researchers, were interviewed and made to answer a questionnaire.

RESULTS

The results showed that there were a number of factors behind the initiation of HIA, which either delayed or accelerated the process. The problems identified were e.g. the prevailing traditional health care focus and the deteriorating health status of the population. There was a lack of multi-intersectoral knowledge, co-operation and function between sectors and actors. Enablers on the other hand were the membership of international organizations which called for new solutions, and the strong political commitment and belief that intersectorality would have a positive effect on health.

CONCLUSION

The actors on the local level would have the capacity to work intersectorally to bring about policy change if HIA was to be more supported/institutionalized.

Plutonium in the air in Kurchatov, Kazakhstan

Weekly air samples of 25000 m(3) volume were taken with two air samplers over a period of one year in 2000-2001 in the town of Kurchatov in Kazakhstan. For another three-month period in 2001, the samplers were run in the city of Astana, about 500 km west of Kurchatov. (137)Cs, Pu and U concentrations were determined from the filters. Pu activities in Kurchatov varied in a 100-fold range; median (239,240)Pu activities were 100 nBq/m(3) and (238)Pu activities 34 nBq/m(3). The corresponding values for Astana were considerably lower: 29 and 9 nBq/m(3), respectively, and in half of the filters the (238)Pu activity was below the detection limit. Plutonium concentration correlated with the amount of dust retained on the filters only at the highest dust loads. Also no correlation between wind speed and the plutonium activity in the filters was observed. Thus, resuspension does not seem to be the mechanism responsible for the airborne plutonium. No clear seasonal variation of Pu air concentration was observed, though levels were somewhat elevated in February to April. There was no correlation between the plutonium and (137)Cs concentrations. In most of the filters the cesium concentration was below the detection limit, but in those filters where it could be detected the cesium concentration was practically constant at 3.9+/-1.6 microBq/m(3). Dose estimation for the inhalation of the airborne plutonium gave a low value of 0.018 microSv/a for the inhabitants in Kurchatov, which is about a thousand times lower than the dose caused by the naturally occurring (210)Po. Air parcel trajectory analysis indicated that the observed Pu activities in the air could not unambiguously be attributed to the most contaminated areas at the Semipalatinsk Test Site.

Hair chromium concentration of northern Finns

OBJECTIVES

The present study is a pilot project for the Finnish AMAP (Arctic Monitoring and Assessment Programme/Human Health) investigations. We examined the exposure of northern Finns to chromium (Cr), because analyses of this metal are not included in the AMAP, and local industry and industry throughout the Kola Peninsula may increase chromium fallout in Finnish Lapland. Chromium exposure and its temporal trend were estimated by analyzing hair of northern Finns collected in 1982 and 1991.

METHODS

After washing the hair samples, chromium analyses were carried out in 1995 by a method developed by Salmela et al. (1981) and Kumpulainen et al. (1982). The Perkin-Elmer 5000 atomic absorption spectrometer used was equipped with a graphite furnace (HGA-400).

RESULTS

Age showed no statistically significant correlation with Cr concentration in hair, but the hair concentration of Cr in men was higher than that in women, both among southern and northern Finns and Sami.

CONCLUSIONS

Chromium levels in the hair of Finns and Sami were too low to result in any health hazard, however, exposure to chromium may have slightly increased during the 1990s.

Purification of metal finishing waste waters with zeolites and activated carbons

Sixteen zeolites and 5 activated carbons were tested for the removal of nickel, zinc, cadmium, copper, chromium, and cobalt from waste simulants mimicking effluents produced in metal plating plants. The best performances were obtained from 4 zeolites: A, X, L, and ferrierite types and from 2 carbon types made from lignite and peat. The distribution coefficients for these sorbents were in the range of 10,000-440,000 ml/g. Column experiments showed that the most effective zeolites for Zn, Ni, Cu, and Cd were A and X type zeolites. The activated carbons, Hydrodarco 3000 and Norit Row Supra, exhibited good sorption properties for metals in aqueous solutions containing complexing agents.

The economics of alcohol

The use of economic arguments with regard to four aspects of alcohol policy is described and discussed. The first aspect is the impact of a potential reduction in alcohol consumption on employment by alcohol production and trade. It is shown that employment is quite independent of the level of consumption. The second aspect is the opportunity for serving the public health and state finance interests at the same time by developing alcohol taxation. The third aspect is the relationship between the public revenue from alcohol and the public costs for alcohol-related problems. A "polluter pays" principle with regard to alcohol would mean higher taxation of alcoholic beverages. The fourth aspect is the need for cost-effectiveness analyses to support the choices by the decision makers between different alcohol policy options. It is concluded that such analyses could have impact on the priorities in public health policy on alcohol.

Alcohol and the future health of Europe

The impact of alcohol consumption on trends in the European health situation is analysed. Particular attention is given to the impact of alcohol on the widening of the East-West health gap in Europe. It is concluded that between 1950-75 the negative health impact of a rapid increase in per capita alcohol consumption in most European countries was hidden behind a strong positive development in many other socio-economic determinants of health. Between 1980 and 1995, health trends have been more closely parallel to trends in alcohol consumption. Changes in alcohol consumption explain a significant proportion of changes in life expectancy, particularly in the newly independent states of the former Soviet Union. Public health policy on alcohol, as part of a general development of public health policies outside the health sector, is important in reducing the East-West health gap and sustaining the positive health trend in western Europe.

Dietary intake and thiamin, iron, and zinc status in elite Nordic skiers during different training periods

This study evaluated how different training periods affect dietary intake and biochemical indices of thiamin, iron, and zinc status in elite Nordic skiers. Subjects were 17 skiers and 39 controls, ages 18-38 yrs. Dietary data were collected by 7-day food records at 3-month intervals. Coefficient of variation (CV) was used to indicate magnitude of seasonal changes. Energy intake for the year (28 food record days) was 3,802 kcal/day (CV 19.1%) in male skiers, 2,754 kcal/day (CV 3.7%) in male controls, 2,812 kcal/day (CV 9.1%) in female skiers, and 2,013 kcal/day (CV 5.9%) in female controls. CVs for thiamin, riboflavin, vitamin C, calcium, magnesium, iron, and zinc intake were 14.1-23.9% (male skiers), 2.9-15.0% (male controls), 4.8-24.5% (female skiers), and 4.3-11.5% (female controls). Seasonal changes in energy, carbohydrate, and micronutrient intakes reflected energy expenditure in male endurance athletes particularly. Erythrocyte transketolase activation coefficients and serum ferritin and zinc concentrations did not differ between skiers and controls. Seasonal variations in these biochemical indices of nutritional status were of the same magnitude in skiers and controls, despite large changes in skiers' physical activity.

Serum cholesterol and vitamins A and E in juvenile chronic arthritis

Serum total cholesterol is decreased during acute infections and in adults with rheumatoid arthritis, probably partly because of enhanced lipid peroxidation. Oxidative stress also causes augmentation of inflammation and tissue damage in arthritic synovium. Therefore, concentrations of serum total cholesterol and the antioxidant vitamins A and E were studied in 125 children with juvenile chronic arthritis. Total serum cholesterol was significantly lower in the patients than in healthy children in most age groups and correlated with the markers of disease activity, haemoglobin and the erythrocyte sedimentation rate. In age- and sex-adjusted stepwise multiple linear regression, serum zinc had a significant predictive value for cholesterol. The vitamin A concentrations in the sera of the patients was virtually the same as in the healthy controls, though serum vitamin E concentrations were low (22.8 +/- 15.2 vs 30.5 +/- 4.3 mumol/l, p less than 0.001). The deficiency in vitamin E was not compensated for by another lipoperoxide antioxidant, glutathione peroxidase. Only serum cholesterol had an independent explanatory significance for vitamin E in multiple linear regression analysis (partial correlation 0.554, p less than 0.001). It is suggested that low vitamin E and impairment of the anti-oxidant protection further contribute to low serum cholesterol values in JCA.

Serum trace elements in juvenile chronic arthritis

We evaluated the serum concentrations of zinc, copper and selenium in 125 patients with juvenile chronic arthritis (JCA). Trace element levels showed distinct abnormalities as compared with those of a large group of healthy children. Serum zinc and selenium concentrations were lower and those of copper higher in children with arthritis than in healthy children and, further, patients with polyarthritis had significantly higher copper and lower zinc levels than those with oligoarthritis. Serum zinc levels showed a direct correlation with hemoglobin and an inverse correlation with values for the erythrocyte sedimentation rate (ESR), whereas copper correlated directly with ESR. Selenium values did not correlate with the activity of the disease, but were low in the patients with arthritis of long duration.

Predictive clinical and laboratory parameters for serum zinc and copper in rheumatoid arthritis

Zinc and copper have important effects on T cell mediated immunity and on neutrophil function, but it is not known how the causes or effects, of low serum zinc and high serum copper relate to the clinical picture of rheumatoid arthritis (RA). In this study serum zinc and copper determined by flame atomic absorption spectrometry and 30 other clinical, immunological, and laboratory parameters in 60 patients with RA were analysed by stepwise multiple linear regression analysis. Joint score index, rheumatoid factor titre, seropositivity, haemoglobin, and C reactive protein (CRP) were among the nine independent variables which together predicted 73% of the serum zinc variation. This suggests that there is an association between the immune-inflammatory rheumatoid process and the serum zinc concentration. CRP alone had only a 3% independent predicting value for serum zinc, however. This suggests that metallothionein mediated sequestration in the liver, induced by interleukin 1, is not an important explanatory factor in a cross sectional study of chronic inflammation. Furthermore, serum zinc did not have any predictive value at all for serum copper concentration. This does not support the hypothesis suggesting that serum zinc deficiency leads to high serum copper by inducing gastrointestinal metallothionein and high caeruloplasmin.

Decreased serum selenium and magnesium levels in drunkenness arrestees

Serum levels of selenium magnesium, copper, zinc and iron were studied in chronic drunkenness arrestees and a healthy control group. The mean serum concentrations of selenium and magnesium were both significantly lower (P less than 0.01) in drunkenness arrestees than in the control subjects. The mean alcohol intake was 190 g of absolute alcohol daily in drunkenness arrestees and 14 g in controls. The erythrocyte glutathione peroxidase concentrations of the study groups did not support poor selenium intake as a principal cause of low selenium concentration in the serum.

Formula feeding results in lower selenium status than breast-feeding or selenium supplemented formula feeding: a longitudinal study

Thirty-two infants completely weaned by age 3.2 mo were randomized into two groups. Unsupplemented group was fed cow's milk-based liquid formula containing 3-5 micrograms Se/L. Se-supplemented group received the same formula supplemented with 20 micrograms Se/L. A third group consisted of exclusively breast-fed infants (51 at age 4 mo, 41 at 6 mo, 12 at 9 mo). Mean serum Se concentration in unsupplemented group decreased from 41 to 31 micrograms/L during the first 2 mo and remained constant until age 6 mo increasing gradually thereafter. In Se-supplemented group it increased steadily from 41 to 68 micrograms/L at age 6 mo and remained constant while supplemented formula was used. In breast-fed group it increased steadily until age 9 mo, between the levels of the two formula-fed groups, when it reached the concentration of Se-supplemented group. At age 12 mo no significant differences were present among the three groups.

Determination of chromium in human milk, serum and urine by electrothermal atomic absorption spectrometry without preliminary ashing

In the present study a Perkin-Elmer 5000 atomic absorption spectrometer equipped with a tungsten--iodide lamp for improved background correction at the 357.9 nm chromium absorption line and an HGA 500 graphite furnace were employed for the direct determination of chromium in human serum, milk and urine. The method of standard additions was used: 0.25-0.75 ng Cr was added to 1 ml samples. Except for urine samples, a dilution of 1 + 1 to 1 + 2 with H2O was necessary in order to obtain correct calibration curves. The average concentration of chromium in all the samples of normal subjects was less than 0.5 ng Cr ml-1. The day-to-day variation for all of the pooled samples was around 10% (relative standard deviation). For urine, the accuracy of the method was tested by comparing the results of another laboratory for the same two round robin samples. Excellent agreement was found between the present method and those of the other laboratory that had used isotope dilution--mass spectrometry and continuum source wavelength modulated echelle--atomic absorption spectrometry to define the chromium concentration in the samples. The detection limit of the method, 0.05 ng Cr ml-1 for urine and serum and 0.1 ng Cr ml-1 for human milk, was sufficient for the biological fluids analyzed. The method was employed for the determination of chromium in 24-h urine samples of maturity onset diabetics supplemented with 20 or 200 micrograms Cr3+ d-1 for six weeks. It was shown that the 24-h urinary chromium excretion accurately indicates the daily dietary chromium intake of these patients.

Electrothermal atomic absorption spectrometric determination of selenium in foods and diets

The validity of 2 electrothermal atomic absorption spectrometric methods for determination of selenium in foods and diets was tested. By using 0.5% Ni(II) as a matrix modifier to prevent selenium losses during the ashing step, it was shown that selenium can be determined in samples containing greater than or equal to 1 microgram Se/g dry wt without organic extraction. The mean recovery tested, using NBS Bovine Liver, was 98%; recovery of added inorganic selenium in Bovine Liver matrix was 100%. In addition, this method gave values closest to the median value of all participating laboratories using hydride generation AAS or the spectrofluorometric method in a collaborative study on high selenium wheat, flour, and toast samples. For samples with concentrations less than 1 microgram Se/g dry wt, separation of selenium from interfering Fe and P ions by organic extraction was necessary. Using inorganic 75Se in meat and human milk matrixes, an ammonium pyrrolidine dithiocarbamate-methyl isobutyl ketone-extraction system with added Cu(II) as a matrix modifier yielded the best extraction recoveries, 97 and 98%, respectively. Accuracy and precision of the method were tested using several official and unofficial biological standard materials. The mean accuracy was within 4% of the certified or best values of the standard materials and the day-to-day variation was 9%. The Se/Fe or Se/P interference limits proved to be low enough not to affect selenium determinations in practically all foods or diets. The practical detection limit of the method was 3 ng Se/g dry wt for 1.0 g dry wt samples.(ABSTRACT TRUNCATED AT 250 WORDS)