Biomedical subjects

L Jorhem

Publications and source records attributed to L Jorhem.

At least 19 recordsLinked to original sources

PubMed1999

Concentration-dependent absorption of aluminum in rats exposed to labile aluminum in drinking water.

The hypothesis was tested that the absorption of labile Al in rats will increase when the Al-binding capacity of food components in the stomach is saturated. Male rats were exposed to 0, 10, 50, or 500 mg labile Al/L in acidic drinking water (pH 3) for 9 wk. The results show that labile Al in drinking water is complexed by feed constituents in the stomach of the rat in vivo, thus causing a nondetectable absorption of Al at 10 mg Al/L. An increased absorption of Al at 50 and 500 mg Al/L was associated with a saturation of the Al-binding capacity of feed components in the lumen of the stomach, causing the appearance of labile Al. Thus, the presence of labile Al in drinking water does not necessarily result in a high Al absorption when the water is ingested, since the bioavailability of labile Al is dependent both on the amount and composition of Al-binding components present in the gastrointestinal tract at the time of ingestion of the water. It is thus not possible to predict the body burden of Al in humans just by measuring the Al concentrations in drinking water. Even a further refining of the exposure measurement to include speciation of Al in the water may not markedly improve the prediction of the Al body burden. Future epidemiological studies must therefore be based on actual measurements of Al concentration in tissues or fluids from the study subjects.

Absorption↗

PubMed1999

Does aluminium stimulate the immune system in male rats after oral exposure?

The influence of oral aluminium exposure on the immune system was studied in rats. Male rats were exposed to soluble and labile Al in acidic drinking water (0-500 mg Al/l) for 7-9 weeks. The concentration of Al in femur bone was higher in rats exposed to 50 and 500 mg Al/l (mean concentration 277 and 599 ng Al/g) than in control rats (150 ng Al/g). The Al concentration in blood plasma could only be quantified in the 500 mg/l group (mean 2.7 ng/ml), whereas the concentrations in the control and 50 mg/l groups were low (< 2 ng Al/ml). Exposure of 4-13-weeks-old rats to the highest Al concentration caused an increased number of splenocytes, whereas exposure of 9-16-weeks-old rats to 500 mg Al/l caused an increased number of thymocytes. Moreover, the proliferative response of splenocytes to the mitogen Con A (2 micrograms/ml) was increased by exposure of the 9-16-weeks-old rats to 500 mg Al/l as compared with the controls. The results indicate that oral Al exposure caused a slight stimulation of some immune functions in the rat at Al plasma concentrations normally found in the human population (< 10 ng Al/ml).

Administration, Oral↗

PubMed1998

Accumulation of cadmium from wheat bran, sugar-beet fibre, carrots and cadmium chloride in the liver and kidneys of mice.

The gastrointestinal absorption and organ distribution of Cd after exposure for 9 weeks to three fibre-rich foodstuffs (wheat bran, sugar-beet fibre and carrots) were determined in mice. Groups of eight mice were given a diet containing 0.05 mg Cd/kg from wheat bran, sugar-beet fibre, carrots or CdCl2 mixed in a semi-synthetic, low-Cd (< 0.007 mg/kg) feed. A control group was fed on the low-Cd semi-synthetic feed. The water consumption, food consumption and the weight of the animals were monitored throughout the study. The feed was changed once weekly and Cd was analysed in the feed at each change. myo-Inositol phosphates (hexa-, penta-, tetra- and tri-) and Zn, Cu, Fe and Ca were also analysed in the diets. After 9 weeks, the mice were killed and liver and kidneys were sampled and analysed for Cd. The group receiving the wheat-bran diet had significantly lower fractional Cd accumulation (% total Cd intake) in the liver and kidneys than the other groups, indicating a lower fractional absorption of Cd. The wheat-bran diet had markedly higher levels of inositol hexa- and pentaphosphates (phytates) and a Zn level that was twice as high as those in the other diets. The higher levels of myo-inositol hexa- and pentaphosphates in the wheat-bran diet most probably contributed more to the lower fractional absorption of Cd than the elevated Zn level, due to the formation of insoluble Cd-phytate complexes. Compared with the wheat-bran diet, the sugar-beet-fibre and carrot diets contained very low levels of myo-inositol penta- and hexaphosphates, and consequently the fractional Cd absorption from these diets was higher.

Animals↗

PubMed1997

Cadmium levels in kidneys from Swedish pigs in relation to environmental factors--temporal and spatial trends.

The kidney cadmium level in pigs slaughtered at the age of 5-7 months was analysed with respect to geographical and temporal trends. During the period 1984-1992, a total of 1051 samples of porcine kidney from 31 abattoirs were analysed for cadmium at the National Food Administration within the control programme for livestock production. The mean kidney cadmium level was 0.11 +/- 0.07 mg/kg wet wt. (mean +/- S.D.). Regression analysis showed that the cadmium concentration in pig kidney has increased by 2% per year. By using Geographic Information System (GIS), geographical trends in cadmium concentration of porcine kidney were analysed and correlated to cadmium levels in moss and pH in the mor layer of podsolized soil. These two parameters explained 60% of the random variation in cadmium levels in porcine kidney. There were significant differences between individual abattoirs, but no significant longitudinal or latitudinal trend was found. Variation in kidney cadmium levels within breeding stocks was investigated. Kidneys from eight stocks, with five pigs from each, were analysed for cadmium concentration. In spite of the homogeneous treatment of the pig within the same stock, kidney cadmium levels varied on average by a factor of two between individuals. There was a significant correlation between cadmium in feed and cadmium levels in porcine kidney (P = 0.002). The temporal increase in cadmium levels in porcine kidney should be further investigated. An increase in cadmium body burden in pig may be an indicator of an increase in human cadmium exposure.

Animal Feed↗

PubMed1997

Cadmium accumulation in liver and kidney of mice exposed to the same weekly cadmium dose continuously or once a week.

Cd levels in blood, liver and kidney of female mice were measured after exposure to Cd as CdCl2 in the food, either continuously (CE group) throughout the week (300 microg Cd/kg feed) or for 24 hr/wk (2100 microg Cd/kg) for 5 wk (occasionally exposed, OE group). In a control group that received feed with Cd levels below the detection limit (< 7 microg/kg), Cd levels in blood, liver and kidneys were below the detection limit after the 5 wk of exposure. The weekly dose of Cd administered to the exposed CE and OE groups was similar (approx. 400 microg Cd/kg mice/wk). The OE group had a higher Cd level in blood and a higher fractional accumulation (% of dose) of Cd in the liver and kidneys compared with the CE group. This indicates that the fractional Cd absorption in the gastrointestinal tract is higher when high Cd doses are ingested occasionally than when low doses are ingested continuously, even if weekly doses are the same. It is hypothesized that this difference in absorption could be due to Cd-induced unspecific damage to the intestinal mucosa, changes in tight-junction permeability caused by Cd, or to a saturation of the Cd-binding capacity of the intestinal mucosa in mice exposed to high Cd levels occasionally.

Animals↗

PubMed1996

Levels of certain trace elements in beef and pork imported to Sweden.

The levels of Pb, Cd, Ni, Cr, Co, Zn, Cu, Mn, As and Se were determined in beef and pork imported to Sweden from six different countries. Samples of Swedish beef and pork were included for comparison. The results of this survey showed in most cases little difference in levels of these elements between the countries and agreed well with the results from our previous studies. All results for Pb, Cd, Ni and As were below the detection limits of 0.007, 0.001, 0.016 and 0.030 mg/kg fresh weight, respectively. Chromium and cobalt were, in both beef and pork, close to, or below, the detection limits of 0.004 and 0.003 mg/kg fresh wt, respectively. The level of selenium in beef varied considerably between countries, from < 0.030 to 0.18 mg/kg fresh wt. The levels of lead and cadmium from this study differed strongly in some cases from what have been reported in surveys from several countries, among them some countries exporting to Sweden. The importance of a rigorous quality control programme is emphasized.

Animals↗

PubMed1995

Lead and cadmium levels in human milk and blood.

Lead and cadmium levels were determined (with AAS) in blood and milk obtained at 6 weeks after delivery from women living in the vicinity of a copper and lead metal smelter and in a control area. Analysis of lead and cadmium were also performed in blood samples obtained at delivery. Accuracy of the analysis was confirmed by the analysis of quality control samples. In general, blood and milk levels of lead and cadmium were low in both areas. At 6 weeks after delivery the lead levels in blood and milk were 32 +/- 8 and 0.7 +/- 0.4 micrograms Pb/l, respectively (total mean +/- S.D., n = 75). Cadmium levels in blood and milk were 0.9 +/- 0.3 and 0.06 +/- 0.04 microgram Cd/l, respectively (n = 75). At delivery the lead levels in blood of women in the smelter area were higher, 38.7 micrograms Pb/l, than the blood lead levels in women from the control area, 32.3 micrograms Pb/l, (P < 0.001). At 6 weeks after delivery there was no difference in blood lead levels between the two groups. In contrast, the lead levels in milk were higher in women from the smelter area, 0.9 microgram Pb/l, than in women from the control area, 0.5 microgram Pb/l, (P < 0.001). No differences in blood cadmium levels were found between the two groups. Milk cadmium levels in women from the control area, 0.07 microgram Cd/l, were somewhat higher (P < 0.01) than in women from the smelter area, 0.05 microgram Cd/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1995

Levels of some trace elements in edible fungi.

A number of common edible fungi were analysed for their contents of Pg, Cd, Cr, Ni, Co, Zn, Cu, Mn and Se. The results indicate that the Cd level in the species Rozites caperata can be as high as several mg/kg fresh weight. In Lycoperdon perlatum and Macrolepiota procera the Pb level was found to be up to 2.5 mg/kg. The Ni level was at or below 0.1 mg/kg in all species, with the exception of Albatrellus ovinus, which had a mean concentration of 0.72 mg/kg. The level of Cr was highest in M. procera with a mean of 0.091 mg/kg. In a single sample of the species Agaricus augustus, the concentration of Co was found to be exceptionally high at 0.28 mg/kg. Zn and Cu levels were highest in L. perlatum and M. procera. Mn levels were fairly similar in the different species. The results of several surveys show that there can be large differences in the concentrations of the same metal (e.g. Pb) in the same species. The Se level was found to be very high in the species Boletus edulis, as has been shown by others. In the other species analysed the level of Se was low.

Agaricales↗

PubMed1995

Characterisation of a fungus reference material, and a guide for use.

A reference material consisting of an edible fungus, Cantharellus tubaeformis, with certified levels of Pb, Cd, Zn, Cu, Mn, Cr, Ni, Co and Fe was produced, primarily for use in a project concerning metal determination in common edible fungi. The C. tubaeformis was dried, homogenised and sieved using non-contaminating equipment. It was then mixed thoroughly before bottling in polythene containers. Homogeneity was checked by multiple analysis of a number of containers, and was found to be satisfactory. Each metal was determined by at least two different methods of analysis. A total of ten laboratories participated in the certification process. All the metals analysed in this certified reference material showed good agreement with the levels found in fresh C. tubaeformis, when the difference in water content was accounted for. This indicates that no contamination of the fungus reference material occurred during the production. It is concluded that the 95% confidence interval for the true mean, as defined for the different metals, is of limited value from the user's point of view. Therefore, a more user-oriented way of presenting the results, based on the within- and between-laboratory standard deviations of the certification process, is suggested. These are 95/95% tolerance intervals within which the user's results should fall. Different intervals are given, one of which indicates the largest acceptable difference between duplicates and another for the acceptable range of future means.

Agaricales↗

PubMed1995

Placental and lactational transfer of lead in rats: a study on the lactational process and effects on offspring.

The effects of placental and lactational exposure to lead (Pb) were studied in suckling rats after long-term exposure of their dams to Pb in drinking water. Dams were given 12 mM Pb-acetate in the drinking water 8 weeks prior to mating and during gestation. One group of dams was also continuously exposed during lactation until day 15. Neonates from Pb-treated dams were cross-fostered at birth to control dams treated with Na-acetate (12 mM) in the drinking water. In the same way, neonates from dams receiving control water were in the same way cross-fostered to Pb-exposed dams. All animals were killed at day 15 of lactation, when measurements were performed. Continuous Pb exposure during gestation and lactation resulted in milk Pb levels approximately 2.5 times higher than the blood Pb levels. When Pb exposure was terminated at parturition the milk Pb levels were at a level similar to those of blood Pb at day 15 of lactation, and only 10% of the milk levels found after continuous Pb exposure. Exposure to Pb via placenta and milk in offspring from dams exposed continuously resulted in more than 6 times higher blood and brain Pb levels than in offspring exposed only via the placenta. Exposure only via milk in offspring from dams exposed to Pb until parturition resulted in higher blood Pb levels than in offspring exposed to Pb only via the placenta. This indicates that the lactational transfer after current or recent exposure of Pb in dams is considerably higher than placental transfer. Offspring in all the exposed groups had decreased ALAD activity in the blood. An exponential relationship between blood Pb levels and ALAD activity was demonstrated in the offspring. Due to the exponential decrease in ALAD activity at increasing blood Pb levels, ALAD is particularly sensitive in reflecting differences in Pb exposure within the lowest range of blood Pb levels. There was a slight effect on weight gain in the offspring. However, there was no effect on milk quality, as measure by milk lipid, protein and calcium concentrations, nor on milk production assessed by the mammary gland RNA and DNA content. This indicates that the effect on weight gain was a direct effect of Pb in the offspring.

Animals↗

PubMed1995

Bioavailability of labile aluminium in acidic drinking water: a study in the rat.

The bioavailability of labile Al (Allab; Al3+, and monomeric hydroxo and sulfato complexes) in drinking water was studied in the rat. The hypothesis was that Allab in drinking water is more available for absorption in the gastro-intestinal tract than Al complexed in the rat feed. Male Sprague-Dawley rats were exposed to 4 mg Al/litre in acidic drinking water (pH 4-5) and 5 mg Al/kg in the feed for 10 wk. The Al intake of these rats was about twice that in a control group of rats that received Al only in the feed. Both a theoretical speciation calculation and a speciation analysis of the water in a flow injection system showed that more than 98% of the Al in the water was present as Allab. However, intake of this water did not result in increased levels of Al in the bone, liver or brain tissue of the rats. Al speciation in a simulated rat stomach indicated that Allab in drinking water is rapidly complexed by feed constituents as the water enters the acidic milieu of the stomach, resulting in a very low concentration of Allab. The concentration of dissolved Al was also low in comparison to the added amount of labile Al. The possibility of complex formation between Allab and feed components in the gastro-intestinal tract should be taken into account in further studies of the bioavailability of drinking water Al in experimental animals and in humans.

Aluminum↗

PubMed1995

Bioavailability of cadmium from crab hepatopancreas and mushroom in relation to inorganic cadmium: a 9-week feeding study in mice.

The bioavailability of Cd from boiled crab hepatopancreas and dried mushroom was studied in relation to that of inorganic Cd (CdCl2). Female Balb/c mice were fed with diets containing 0.4 ppm Cd from either boiled crab (Cancer pagurus) hepatopancreas or dried mushroom (Agaricus augustus), or as inorganic Cd (CdCl2). A control group received low Cd (< 0.007 ppm) feed, and did not accumulate detectable levels of Cd during 9 wk of exposure. Using Cd accumulation in the liver and kidney as a measure of Cd absorption, it was indicated that the bioavailability of Cd from boiled crab hepatopancreas is slightly lower than that of Cd from mushroom and inorganic Cd. Fractionation of Cd in boiled crab hepatopancreas and mushroom indicated that Cd in crab hepatopancreas mainly is associated with denaturated proteins with low solubility, whereas a large fraction of Cd in dried mushroom is associated with soluble ligands. This difference in speciation of Cd may be a reason for the lower bioavailability of crab Cd than that of mushroom Cd. The difference in bioavailability is, however, low and as a safety measure it is recommended that human consumption of both crab hepatopancreas and wild mushrooms with high Cd levels should be restricted.

Animals↗

PubMed1994

Trace elements in crayfish: regional differences and changes induced by cooking.

The concentrations of Pb, Cd, Zn, Cu, Ni, Cr, Mn, Co, As, and Se were determined in the abdominal muscle and hepatopancreas from raw and cooked crayfish of Astacus astacus (L.) and Pacifastacus leniusculus (Dana), both of Swedish origin. After cooking, the concentrations of Cd, Ni, and Co in the hepatopancreas showed a decrease and the concentrations of Pb, Cu, and Mn in the abdominal muscle showed an increase. Metal and metalloid concentrations were also determined in the abdominal muscle and hepatopancreas of commercially caught and cooked crayfish, including Astacus leptodactylus (Esch.) and Procambarus clarkii (Girard), from China, Spain, Sweden, Turkey, and USA. Most of the elements showed little variation except for cadmium in the abdominal muscle of P. leniusculus from California, which was markedly higher (mean = 0.082 mg/kg) than the others (mean = 0.004 mg/kg). Metal and metalloid concentrations in hepatopancreas varied greatly within as well as between countries. In the hepatopancreas from P. leniusculus from a Swedish lake the manganese concentrations were markedly higher than in any other crayfish. The intake of cadmium from crayfish inhabiting uncontaminated waters will be low if the hepatopancreas is not consumed.

Animals↗

PubMed1992

Lead poisoning in cattle--transfer of lead to milk.

The transfer of lead to milk in cattle in relation to blood lead levels and the uptake of lead in edible tissues was studied for an accidental exposure over 1 or 2 days to lead in excessive amounts from the licking of burnt storage batteries. The degree of exposure was monitored by determination of blood lead levels. Milk and blood samples were taken from eight cows, without acute symptoms of lead poisoning, during a period of 18 weeks. Two weeks after the accidental exposure, lead levels (mean +/- SD) in milk were 0.08 +/- 0.04 mg kg-1 and in blood 0.36 +/- 0.04 mg kg-1 in six of the cows. The relationship between lead concentration in blood and those in milk was found to be exponential and could be expressed by the equation: log y = 3.19x - 2.36 (r = 0.85, p less than 0.001), where y and x are the lead concentrations in milk and blood, respectively. The lead level in milk was relatively constant up to a blood lead level of 0.2-0.3 mg kg-1, and increased sharply at higher blood levels. The biological half-life of lead in blood was shown to be approximately 9 weeks. In eight acutely sick cows, which were emergency slaughtered, the range of lead levels in edible muscle tissue was 0.23-0.50 mg kg-1 wet weight. Very high concentrations were found in the kidneys, with a range of 70-330 mg kg-1, and in the livers, with a range of 10-55 mg kg-1. Four of the cows were pregnant, in the first or second month of gestation, during the episode of exposure. The lead exposure was not found to disturb the gestation or development of the fetuses.

Animals↗

PubMed1992

Aluminium in foodstuffs and diets in Sweden.

The levels of aluminium have been determined in a number of individual foodstuffs on the Swedish market and in 24 h duplicate diets collected by women living in the Stockholm area. The results show that the levels in most foods are very low and that the level in vegetables can vary by a factor 10. Beverages from aluminium cans were found to have aluminium levels not markedly different from those in glass bottles. Based on the results of the analysis of individual foods, the average Swedish daily diet was calculated to contain about 0.6 mg aluminium, whereas the mean content of the collected duplicate diets was 13 mg. A cake made from a mix containing aluminium phosphate in the baking soda was identified as the most important contributor of aluminium to the duplicate diets. Tea and aluminium utensils were estimated to increase the aluminium content of the diets by approximately 4 and 2 mg/day, respectively. The results also indicate that a considerable amount of aluminium must be introduced from other sources.

Aluminum↗

PubMed1992

Integrated personal monitoring of cadmium exposure in Sweden.

Methods for the personal monitoring of human exposure to cadmium from air, food and beverages were studied in a group of 15 non-smoking women in Stockholm. Particles in the breathing zone air and duplicates of all food and beverages ingested were collected during seven consecutive days, as were faeces corresponding to the food ingested. Spot samples of blood and urine were also taken. The main sampling problems were caused by the noise of the personal air monitors and the short operation time of the batteries. On average, dietary cadmium (8.5 micrograms per day) contributed 99% of the total cadmium absorbed. There were large day-to-day variations in intake, most peaks corresponding to the consumption of seafood. Faecal cadmium was shown to reflect the total amount of cadmium ingested. There was a significant (p < 0.05) correlation between cadmium concentrations in blood (median 0.3 microgram/l) and average daily dietary intake of cadmium, but the blood cadmium levels could vary by a factor of four at one and the same average daily intake. The median urinary cadmium level was 0.2 microgram/l.

Adult↗

PubMed1991

Personal monitoring of lead and cadmium exposure--a Swedish study with special reference to methodological aspects.

Methods for determining personal exposure to lead and cadmium were tested in Stockholm in 1988. Lead and cadmium in breathing-zone air, 24-h duplicate diets, and feces of 15 nonsmoking women (27-46 years of age) were studied. Blood was collected at the beginning of and immediately after the test period (seven consecutive days). An extensive quality assurance program was included. Most technical problems were encountered in the 24-h collection of airborne particles. The pumps were noisy, and the batteries had to be recharged every 6-8 h. The lead and cadmium levels in feces were found to be useful indicators of the total ingested amounts of these metals. Because of the large day-to-day variation in the dietary intake of lead and cadmium, the sampling period for duplicate diets and feces should be at least 5-6 d.

Adult↗

PubMed1989

The levels of zinc, copper, manganese, selenium, chromium, nickel, cobalt, and aluminium in the meat, liver and kidney of swedish pigs and cattle.

The levels of zinc, copper, manganese, selenium, chromium, nickel, cobalt, and aluminium were determined in samples of meat, liver and kidney from pigs and cattle from Swedish slaughterhouses. The results have been compared with those reported from other investigations carried out in recent years. For zinc, copper, manganese and selenium, the mean levels found in the different tissues were very similar to those reported in previous studies. The mean levels of chromium and nickel were found to be in the range less than 0.010-0.015 mg/kg, regardless of the type of tissue. Cobalt levels ranged from 0.001 to 0.043 mg/kg, the highest levels being in the liver samples. The mean levels of aluminium were between 0.024 and 0.068 mg/kg. Tissues from cattle contained approximately twice as much aluminium as tissues from pigs. Analytical quality assurance was carried out by analysing standard reference materials. A great effort was made to minimize and check contamination. This may partly explain the fact that the levels of chromium, nickel, and aluminium found in the present study are among the lowest reported.

Aluminum↗