Landscape history improves detection of marginal habitats on semi-natural grasslands.

Semi-natural grassland habitats have markedly declined from their historical coverage, thus causing substantial losses for agricultural biodiversity and establishing a consequent need to spot the remaining habitat patches. These patches are generally remnants of once larger habitat areas, formed by uninterrupted and low-intensity management for centuries, but then later being isolated and fragmented into smaller pieces. In the light of this development, past landscape phases have a crucial role for the present existence of semi-natural grasslands. The importance of historical factors has been indicated in many studies but evaluation of their added value, or actual site-specific effects compared to observations of only the present landscape characteristics, is not generally provided. As data related to the past is often difficult to obtain, tedious to process and challenging to interpret, assessment of its advantages and related effects - or consequences of potential exclusion - would be needed. In this study, we used maximum entropy approach to model the distribution of Fumewort (Corydalis solida) which in the study area is a good indicator of valuable semi-natural habitats. We constructed three different models - one based on only the contemporary environment with expected indicators of habitat stability, one solely on the historical landscape phases and long-term dynamics, and one combining variables from the past and the present. Predictions of the three models were validated and compared with each other, followed by an analysis indicating the similarity of model results with known Fumewort occurrences. Our results indicate that present landscapes may provide workable surrogates to delineate larger core habitats, but utilization of historical data markedly improves the detection of small outlying patches. These conclusions emphasize the importance of previous landscape phases particularly in detecting marginal semi-natural grassland habitats, existing in contemporarily suboptimal conditions and being prone to disappear if no further actions are taken.

Longitudinal study of chromium in human milk.

Using low temperature ashing and graphite furnace atomic absorption, the concentration of chromium in breast milk samples of 10 breast-feeding mothers was measured and the chromium intake of their totally breast-fed infants was evaluated. Ten samples were collected during 8 to 18 days and five samples during 47 to 54 days and 128 to 159 days of lactation. The milk samples represented every feed during a period of 24 hr and contained foremilk and hindmilk in equal proportions. The mean chromium concentration in the breast milk was 0.39 (SD 0.15) ng/ml and the intake 0.27 (SD 0.11) microgram/day. The mean chromium concentration, or intake in the breast milk did not significantly change with advancing stages of lactation.

Selenium status of exclusively breast-fed infants as influenced by maternal organic or inorganic selenium supplementation.

A longitudinal dietary Se supplementation study on lactating mothers was performed to determine the possibilities of improving the Se status of exclusively breast-fed infants. A total of 200 mothers randomized into three groups received either no Se supplements, 100 micrograms of selenite, or 100 micrograms of yeast-Se daily. Maternal and infant serum Se concentrations showed a linear correlation during exclusive breast-feeding. Yeast-Se in the dose administered was safe and more effective than selenite in increasing the Se concentrations of maternal serum and milk, and infant serum. The mean estimated daily Se intakes of the infants were 7.7 +/- 2.2, 8.9 +/- 2.2, and 11.5 +/- 4 micrograms, in the control, selenite, and yeast-Se groups respectively. Though the infant Se intakes of the unsupplemented and selenite-supplemented mothers were below the lower limit of the safe and adequate range as set by the US National Research Council, their serum Se concentrations increased steadily over the 6-mo study period. As maternal serum Se also increased by over 50% during the same period the results suggest that a maternal daily intake of 50-75 micrograms is adequate during lactation.

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.

Decreased serum selenium in alcoholics as related to liver structure and function.

Serum selenium was evaluated in relation to hepatic structure and function in 46 alcoholics with diagnostic liver biopsy classified into 4 groups by hepatic histology. Their serum selenium concentration varied from 12 to 88 micrograms/l and was lower (p less than 0.001) in all groups of alcoholics, ie patients with normal liver (53.0 +/- 20.7 micrograms/l, mean +/- SD), fatty liver (55.8 +/- 21.2 micrograms/l), alcoholic hepatitis (46.0 +/- 14.1 micrograms/l), and cirrhosis (41.1 +/- 12.8 micrograms/l), than in 25 healthy controls (88.7 +/- 11.0 micrograms/l). Serum selenium level was related to the severity of liver disease, and most reduced in subjects with decompensated alcoholic cirrhosis. Their serum selenium level (29.2 +/- 13.7 micrograms/l) was below (p less than 0.05) that obtained in alcoholics with normal liver and fatty liver respectively. Both inadequate dietary selenium intake and alcohol-induced changes in hepatic structure and function may have contributed to the decrease of serum selenium in the subjects studied.

Effect of inorganic chromium supplementation on glucose tolerance, insulin response, and serum lipids in noninsulin-dependent diabetics.

A placebo-controlled double-blind cross-over study was carried out to assess the effect of chromium supplementation (200 micrograms trivalent chromium daily for 6 wk) on glucose tolerance, insulin response, long-term diabetic control, and serum lipids in 10 noninsulin-dependent diabetics aged 37 to 68 yr. After chromium supplementation 24-h urinary chromium excretion showed a 9-fold increase indicating a positive chromium balance in the subjects. There was no significant difference between chromium supplementation and placebo periods in glucose tolerance and in fasting or 2-h postglucose serum insulin levels but the 1-h postglucose serum insulin level was slightly lower on chromium supplementation than on the placebo (55 +/- 9.0 versus 64 +/- 11; p less than 0.01, paired t test). Serum total cholesterol and triglycerides and their high-density, low-density, and very low-density lipoprotein subfractions showed no change after chromium supplementation as compared to the placebo period.

Serum selenium concentration, glutathione peroxidase activity and lipid peroxides in a co-twin control study on multiple sclerosis.

Serum selenium concentration, glutathione peroxidase activity and lipid peroxides were determined in patients with multiple sclerosis (MS). The series consisted of 13 same-sexed twin pairs derived from the Finnish Twin Cohort of 15,815 pairs. Fourteen subjects had a definite and 1 a probable MS, and their 11 co-twins showed no evidence of central nervous system disease. No statistical differences were observed, but the 3 patients with active progressive MS had a higher mean level of lipid peroxides than the rest of the patients. We suggest that serum lipid peroxidation may be involved in the activity of MS.

Determination of flavonoids in plant material by HPLC with diode-array and electro-array detections.

A high-performance liquid chromatographic (HPLC) method with in-line connected diode-array (DAD) and electro-array (EC) detection to identify and quantify 17 flavonoids in plant-derived foods is described. Catechins were extracted from the samples using ethyl acetate, and quantification of these compounds was performed with the EC detector. Other flavonoids were quantified with DAD after acid hydrolysis. The methods developed were effective for the determination of catechins and other flavonoids in plant-derived foods. Responses of the detection systems were linear within the range evaluated, 20-200 ng/injection (DAD) and 20-100 ng/injection (EC), with correlation coefficients exceeding 0.999. Coefficient of variation was under 10.5%, and recoveries of flavonoids ranged from 70 to 124%. Purity of the flavonoid peaks was confirmed by combining the spectral and voltammetric data.

Comparison of in-line connected diode array and electrochemical detectors in the high-performance liquid chromatographic analysis of coenzymes Q(9) and Q(10) in food materials.

In-line connected electrochemical (EC) and diode array (DAD) detectors were compared in the reversed-phase high-performance liquid chromatographic (RP-HPLC) analysis of coenzymes Q(9) and Q(10) in some food materials (beef steak, beef heart, Baltic herring fillet, and rye flour). Coenzymes Q(9) and Q(10) were extracted from the samples using a 5:1 n-hexane-ethanol mixture. Coefficient of variation (CV%) of quadruplicate or quintuplicate determined samples for coenzymes Q(9) and Q(10) was <10 by both EC detector and DAD. Responses of the detection systems were linear in the range evaluated, 10-200 ng/injection, and had correlation coefficients exceeding 0.999. Recoveries of added coenzymes Q(9) and Q(10) varied 73-105% for DAD and 74-103% for EC detector, respectively. Detection limits for coenzymes Q(9) and Q(10) using the DAD system were 4 and 6 ng/injection, respectively, and 0.2 and 0.3 ng/injection by EC detection. Results derived from the two detection systems were generally similar. However, although EC detector was 20-fold more sensitive, the selectivity was, in some cases, poorer than that of DAD.

Determination of anthocyanidins in berries and red wine by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for the determination of anthocyanidins from berries and red wine is described. Delphinidin, cyanidin, petunidin, pelargonidin, peonidin, and malvidin contents of bilberry (Vaccinium myrtillus), black currant (Ribes nigrum), strawberry (Fragaria ananassa cv. Jonsok), and a Cabernet sauvignon (Vitis vinifera) red wine were determined. The aglycon forms of the anthocyanins present in the samples were revealed by acid hydrolysis. A reversed phase analytical column was employed to separate the anthocyanidins before identification by diode array detection. The suitability of the method was tested by determining the recovery (95-102% as aglycons and 69-104% from glycosides) for each anthocyanidin. Method repeatability was tested by charting the total aglycon content of two samples over a period of 14 analyses and determining the coefficients of variation (1.41% for bilberry and 2.56% for in-house reference material). The method developed proved thus to be effective for reliable determination of anthocyanidins from freeze-dried berry samples and red wine. The total anthocyanidin content of the tested samples was as follows: in-house reference material, 447 +/- 8 mg/100 g; strawberry, 23.8 +/- 0.4 mg/100 g; black currant, 135 +/- 3 mg/100 g; bilberry, 360 +/- 3 mg/100 g; and Cabernet sauvignon red wine, 26.1 +/- 0.1 mg/100 mL.

Contents of vitamins, mineral elements, and some phenolic compounds in cultivated mushrooms.

The aim of the study was to determine the contents of mineral elements (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se), vitamins (B(1), B(2), B(12), C, D, folates, and niacin), and certain phenolic compounds (flavonoids, lignans, and phenolic acids) in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinus edodes, and Pleurotus ostreatus. Selenium, toxic heavy metals (Cd, Pb), and other mineral elements were analyzed by ETAAS, ICP-MS, and ICP methods, respectively; vitamins were detected by microbiological methods (folates, niacin, and vitamin B(12)) or HPLC methods (other vitamins), and phenolic compounds were analyzed by HPLC (flavonoids) or GC--MS methods (lignans and phenolic acids). Cultivated mushrooms were found to be good sources of vitamin B(2), niacin, and folates, with contents varying in the ranges 1.8--5.1, 31--65, and 0.30--0.64 mg/100 g dry weight (dw), respectively. Compared with vegetables, mushrooms proved to be a good source of many mineral elements, e.g., the contents of K, P, Zn, and Cu varied in the ranges 26.7--47.3 g/kg, 8.7--13.9 g/kg, 47--92 mg/kg, and 5.2--35 mg/kg dw, respectively. A. bisporus/brown contained large amounts of Se (3.2 mg/kg dw) and the levels of Cd were quite high in L. edodes (1.2 mg/kg dw). No flavonoids or lignans were found in the mushrooms analyzed. In addition, the phenolic acid contents were very low.

Cd, Fe and Zn content of the epiphytic lichen Hypogymnia physodes in a Finnish suburb.

The epiphytic lichen Hypogymnia physodes was analysed for its content of cadmium, iron and zinc in a suburb of Helsinki. The metal contents were slightly higher than those from unpolluted areas in central Finland. Elevated concentrations were found in the vicinity of a big shipyard.

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.

Chromium content of foods and diets.

Comparatively few valid data are available on the chromium content of foods and on the dietary chromium (Cr) intake of various populations. This is chiefly because of the difficulties encountered in contamination control during sampling, sample pretreatment, and analysis. Moreover, there are several analytical problems involved that are mostly owing to the low concentration level of Cr in foods. However, with the recent establishment of food reference materials with certified low concentrations of Cr, the analytical validity of studies on Cr content of foods and on its dietary intake by various populations can be ascertained. With the exception of herbs and condiments, and certain other special food items with a relatively low average consumption rate, such as tea, coffee, and some candies, most foods contain Cr below 100 micrograms/kg. Staple foods, particularly cereals and milk, are very low (less than or equal to 10 micrograms/kg) in Cr, showing little or no geographic variation. Food processing may increase food Cr content depending on the process. Processes, such as meat grinding and homogenization using stainless-steel equipment, very strongly increase the Cr content of foods. Also, acidic fruit juices in contact with steel cans are high in Cr, whereas cooking in aluminium vessels reduces the Cr content of foods. Average dietary Cr intake seems to fluctuate considerably among countries. In many developing countries, such as Brazil, the Sudan, and Iran, the dietary intake is high, from 50-100 micrograms/d, whereas in certain developed countries, such as Finland, Sweden, Switzerland, and the US, the intake is 50 micrograms/d or lower and, consequently, at or below the estimated safe and adequate daily dietary intake range of 50-200 micrograms/d established by the US National Academy of Sciences. The average Cr content of human milk is below 0.5 micrograms/L, thus resulting in a very low average intake of 0.3 microgram Cr/d by exclusively breast-fed infants in the US and Finland.

Serum selenium, glutathione peroxidase, lipids, and human liver microsomal enzyme activity : A double-blind controlled trial of selenium supplementation.

This study evaluated selenium status in relation to lipid peroxidation, liver microsomal function, and serum lipids in humans. Serum selenium concentration, glutathione peroxidase (GSH-Px) activity, liver microsomal enzyme activity, assessed by plasma antipyrine clearance (AP-CL) rate, and serum lipids were determined in 23 healthy subjects in a double-blind placebo-controlled trial of selenium supplementation. The low selenium concentration (74.0±14.2 µg/L, mean±SD) is attributable to the low selenium content of the diet. Subjects with the lowest selenium levels (n=11) had reduced serum GSH-Px activity, AP-CL rate, high-density lipoprotein cholesterol (HDL-C), and total cholesterol (T-C) as compared with subjects with higher selenium concentrations (n=12). Low AP-CL rates were associated with low HDL-C: T-C ratios. Selenium supplementation, 96 µg/d for 2 wk, increased serum selenium, GSH-Px activity, and the HDL-C: T-C ratio. The results suggest that a low serum selenium level is associated with a decrease in liver microsomal enzyme activity and serum HDL-C and T-C concentrations. Selenium supplementation in subjects with low serum selenium may favorably influence relations between serum lipoproteins connected with the development of atherosclerotic vascular disease.

Factors affecting the selenium intake of people in Transbaikalian Russia.

The selenium concentration in foods grown and consumed and in plasma, red blood cells, and toenails of people living in the district of Chita in the transbaikalian part of Russia were studied in August 1991. Preliminary results from the area have suggested low selenium intakes and the possible occurrence of cardiomyopathy (Keshan disease) in the population. A low selenium concentration in foods grown locally was found: mean selenium concentration in wheat grains was 1, 5, and 28 micrograms/kg, respectively, in three villages studied, that of oats was between 3-6 micrograms/kg, and of cow's milk 10-27 micrograms/kg dry matter. The selenium concentration of bread was considerably higher, between 87-337 micrograms/kg dry wt, presumably because wheat imported from the US had been used for baking. Occasional samples of pork, beef, and mutton contained between 32-218 micrograms selenium/kg dry wt. Low selenium concentrations were observed in samples of soil and river water. The mean plasma selenium concentration of 52 persons was 1.02 mumol/L, including 33 children and 19 adult subjects. The selenium concentrations in red blood cells and toenails were 1.95 mumol/L and 0.61 mg/kg, respectively. No symptoms of heart disease caused by selenium deficiency were observed. It is concluded that the selenium status of people was fairly good thanks to the contribution to dietary intake of imported wheat with a high selenium content. As the selenium concentration was very low in foods grown in the area, the selenium intake of the population will be reduced to a very low level if only locally produced foods are consumed.

Low serum selenium and glutathione peroxidase activity in patients receiving short-term total parenteral nutrition.

Selenium status was determined in 15 consecutive postoperative patients receiving short-term total parenteral nutrition (TPN) using both serum selenium concentration and glutathione peroxidase (GSH-Px) activity as an indicator of body selenium status. The serum selenium concentration was significantly (p less than 0.001) lower in TPN patients (0.52 +/- 0.16 mumol/l, mean +/- SD) than in age- and sex-matched controls (1.08 +/- 0.17 mumol/l). Serum selenium in TPN patients ranged from 0.28 to 0.79 mumol/l and was associated with the duration of TPN. The lowest selenium values was found in patients who had received TPN over 3 weeks (0.35 +/- 0.06 mumol/l) as compared to patients receiving TPN for 1-3 weeks (0.61 +/- 0.13 mumol/l; p less than 0.01). Serum GSH-Px activity in TPN patients was also low (116 +/- 21 U/l) and ranged from 75 to 159 U/l. A significant positive correlation was found between serum selenium and GSH-Px activity (r = 0.520; p less than 0.05) whereas serum selenium and GSH-Px activity did not correlate significantly with liver function tests and body mass index. This study suggests that also short-term TPN patients may be at risk of selenium deficiency.

Effect of maternal dietary selenium intake on selenium levels in breast milk.

The average dietary selenium intake in Finland is naturally low, approximately 30 micrograms/d, when domestic grain is exclusively consumed. Selenium concentrations were determined in 46 individual breast milk samples collected after 1, 2, and 3 months of lactation in 1980, when the average Finnish dietary selenium intake was approximately 50 micrograms/d due to consumption of high selenium US grain. Selenium concentrations were characterized by a pattern of slight decline with advancing stages of lactation: 11.8 +/- 1.7 micrograms/l (n = 13), 10.9 +/- 1.9 micrograms/l (n = 18) and 10.0 +/- 1.9 micrograms/l (n = 15) at 1, 2 and 3 months post partum, respectively. This pattern, however, contrasts strongly to that found in a 1976 set of breast milk samples: 10.7 +/- 1.6 micrograms/l (n = 13) and 5.8 +/- 1.2 micrograms/l (n = 13) at 1 and 3 months post partum, respectively. The dietary selenium intake of the subjects was determined to be 33 +/- 13 micrograms/d during the course of lactation. Analytically, the results of these studies are analogous, as the same investigator determined both sets of samples by exactly the same analytical procedure.

Longitudinal study on the dietary selenium intake of exclusively breast-fed infants and their mothers in Finland.

The dietary selenium intakes of a group of 13 lactating women living in the Helsinki metropolitan area and those of their 10 exclusively breast-fed infants were studied twice during the course of lactation. The first survey period of the women ranged from 6 to 8 weeks post-partum and the second from 17 to 22 weeks post-partum. The selenium intakes of the infants were determined at 1 and 3 months post-partum. In addition, the concentrations of selenium in the breast milk of four of the mothers were determined 6 months post-partum. Milk samples were collected by a method eliminating errors due to diurnal variations and variations during a single feeding. The validity of the analytical method employed was confirmed by means of an interlaboratory collaboration. The level of selenium concentration in the breast milk fell significantly (P less than 0.0005) from 10.7 +/- 1.6 micrograms/l at 1 month of lactation to 5.8 +/- 1.2 micrograms/l at 3 months of lactation, but remained at that level for up to 6 months of lactation (5.6 +/- 0.4 micrograms/l). The total dietary selenium intake of the infants fell significantly (P less than 0.0005) from 8.0 +/- 1.8 micrograms/d to 4.7 +/- 1.1 micrograms/d at 1 and 3 months post-partum, respectively. The mean maternal dietary selenium intake was 36 +/- 13 micrograms/d during the first survey period and 30 +/- 12 micrograms/d during the second survey period.(ABSTRACT TRUNCATED AT 250 WORDS)