Biomedical subjects

Y Thomassen

Publications and source records attributed to Y Thomassen.

At least 37 records · Page 2Linked to original sources

PubMed1999

Self-reported ethnic status of delivering women, newborn body mass index, blood or urine concentrations of toxic metals, and essential elements in sera of Norwegian and Russian Arctic populations.

UNLABELLED: As part of the Arctic Monitoring and Assessment Programme (AMAP), we assessed pregnancy outcome among Sami and Norwegian populations of Finnmark County in Norway and Russians living in the Kola Peninsula of Russia using body mass index of the newborn child (BMIC) as the main indicator; concentrations of essential and toxic elements in biological fluids of delivering women and their children served as additional sources of information. At the hospitals of Hammerfest and Kirkenes in the period November 1993-June 1994 a total of 107 consecutive women gave birth to a child, of whom 15 regarded themselves as Sami. The Russian group (N = 151) delivered their children in the same period. The Sami women were significantly older than the Russian group (28.5 versus 25.1 years, p = 0.04). The mean birth weight was significantly lower in the Sami group compared to non-Sami Norwegians (p = 0.01), but was of comparable magnitude to that recorded in Russia (p = 0.4). For BMIC, the Sami and non-Sami Norwegian results were similar (p = 0.2); both were significantly higher than in Russia (p < 0.001). The essential elements copper, zinc, selenium and iron (as ferritin) in serum showed no differences between the groups, although relatively low levels of serum zinc were documented in all populations studied. Blood cadmium concentrations were strongly related to smoking frequency. Blood lead and urinary nickel levels were significantly higher for the Russian mothers, but did not reach levels of medical concern. CONCLUSION: No ethnic differences in concentrations of essential elements in biological fluids, nor of cadmium and mercury, were observed. However, national differences for lead and nickel were evident. Because of small sample size, these conclusions need confirmation. The similar BMIC values observed for the non-Sami Norwegian and Sami newborns, compared to the Russian group, suggest that BMIC may serve as a good indicator of the nutritional status and possibly also the general health condition of neonates.

Adolescent↗

PubMed1999

Concentrations of essential trace elements in maternal serum and the effect on birth weight and newborn body mass index in sub-arctic and arctic populations of Norway and Russia.

BACKGROUND: This project is part of an assessment of the impact of environmental factors on human health in the Kola Peninsula of Russia and the neighboring arctic area of Norway. Pregnant women and their newborns were studied to explore a relationship between maternal status of essential metals and birth weight. METHODS: Life-style information and serum specimens were collected from at least 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities (N=151 and 167, respectively). Pregnancy outcomes were verified by consulting medical records. Copper, selenium and zinc in serum were determined by atomic absorption spectrometry and ferritin by an automated analyzer method. RESULTS: Mean birth weight and child's body mass index (BMIC) were significantly lower in the Russian group (p<0.001), with or without adjustment for gestational age. Copper, iron (as ferritin) and selenium serum concentrations were in the normal range, while zinc levels in both countries were mostly below the lower limit (10.8 micromol/L) of reported reference intervals. A positive correlation between zinc and birth weight or BMIC was only observed for concentrations exceeding 10.8 micromol/L. Analysis by quartiles showed that maternal urinary creatinine and birth weight were negatively correlated (p=0.001). The influence of the different elements on BMIC, grouped by quartiles, was significantly positive only for selenium (p=0.03) and ferritin (p=0.02), while there was no significant relationship for copper or zinc. Adjustment of birth weight and BMIC for gestational age did not alter substantially the various associations indicated. CONCLUSIONS: With the exception of zinc, the mineral status of delivering women in arctic and sub-arctic regions of Norway and western Russia appears to be adequate. The significantly lower BMIC for the Russian group suggests the likely occurrence of nutritional deficiencies during pregnancy in Russia. However, the significant contribution of a country factor in the predictive model implies that the maternal serum trace-element concentrations explored in this study are incomplete indicators of fetal undernourishment.

Adult↗

PubMed1999

Blood lead and cadmium and birth weight among sub-arctic and arctic populations of Norway and Russia.

BACKGROUND: Delivering women and their newborns in the Kola Peninsula of Russia and the neighboring arctic area of Norway were studied to explore relationships between maternal cadmium and lead status and birth weight as a pregnancy outcome. METHODS: Life-style information, maternal blood and cord blood specimens were collected from 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities. Pregnancy outcomes were verified by consulting medical records. Lead and cadmium were determined in the blood samples by electrothermal atomic absorption spectrometry. RESULTS: The median blood-cadmium concentration for the Russian mothers was 2.2 nmol/L (n = 148) versus 1.8 nmol/L in the Norwegian group (n = 114, p = 0.55). A weak association was observed between maternal cadmium and amount smoked (r = 0.30, p<0.001); no correlation was found between maternal blood cadmium and birth weight. The corresponding maternal lead values were 0.14 (Russia) and 0.06 micromol/L (Norway), p<0.001. The latter lead concentration constitutes one of the lowest adult population values reported to date. Maternal and cord blood lead levels were strongly correlated (r = 0.88, p<0.001). In a multivariate linear regression model, maternal blood lead was recognized as a negative explanatory variable (p<0.05) for birth weight and child's body mass index (BMIC), with or without adjustment for gestational age. A similar association was suggested by ANOVA-analysis of maternal blood lead by quartiles. CONCLUSION: Maternal blood-lead level as an environmental factor is an apparent predictor of low birth weight and BMIC. It reduced substantially the contribution of a country factor in explaining the observed differences in birth weight.

Adult↗

PubMed1998

[Mercury exposure from dental amalgam. Risk assessment and clinical evaluation].

Inorganic mercury is absorbed in small amounts from dental amalgam fillings. Exposure can be calculated by measuring the level of mercury in the blood or urine (u-Hg). The average u-Hg in Norwegians is approximately 2-3 micrograms/g creatinine (approximately 1-2 nmol/mmol creatinine). Classic signs of mercury poisoning occur in a fraction of long-term exposed subjects with u-Hg > 100 micrograms/g creatinine (56 nmol/mmol creatinine). Subtle effects (e.g. enzymuria, altered selenium metabolism, and changes in tremor spectra) have been reported in humans at average levels of 20-35 micrograms/g creatinine (approximately 11-20 nmol/mmol creatinine). There is widespread concern about possible adverse effects of mercury from amalgam fillings. Data on exposure-response relationships make it less likely that low-level mercury exposure from amalgam fillings should cause symptoms or physical signs. Studies of the association between symptoms and amalgam fillings have been negative. Patients with symptoms allegedly caused by mercury from amalgam should undergo thorough medical examination. Based on the patient's symptoms and physical signs adequate time should be allowed for careful recording of medical history, physical examination and relevant laboratory tests.

Dental Amalgam↗

PubMed1998

Selenium in human male reproductive organs.

The objective of the study was to obtain information on the concentration and distribution of selenium throughout the human male reproductive tract. Material was removed at autopsy from 41 men who had died suddenly and unexpectedly. Semen samples were also provided from 184 men attending an andrology clinic for fertility investigation and from 32 healthy volunteers. Significant positive correlations in the selenium concentration were demonstrated between the different reproductive organs, the testis having the highest concentrations. No correlation was found between the concentration of selenium in the genital organs and liver, kidney or blood, suggesting that its uptake and/or biochemical activity in the reproductive organs may be controlled by similar mechanisms not shared by the other organs. No significant age-dependent changes could be detected in tissue selenium concentrations. In a group of men under fertility investigation, a significant positive correlation was obtained between seminal plasma concentrations of selenium and concentrations of spermatozoa in the same ejaculate. A significant positive correlation between concentrations of zinc and selenium in the same ejaculates indicated that selenium may arise largely from the prostate gland.

Adolescent↗

PubMed1998

Urinary nickel excretion in populations living in the proximity of two russian nickel refineries: a Norwegian-Russian population-based study.

The Russian nickel refineries located in the cities of Nikel and Zapolyarny close to the Norwegian border are responsible for extensive sulfur dioxide and nickel pollution, as well as severe ecological damage in both countries. The aim of our study was to investigate human nickel exposure in the populations living on both sides of the Norwegian-Russian border. The design was a cross-sectional population-based study of adults aged 18-69 years residing in Sor-Varanger municipality, Norway, and Nikel and Zapolyarny, Russia, during 1994 and 1995. Individual exposure to nickel was assessed by measurements of nickel in urine using electrothermal atomic absorption spectrometry. For controls, urine was collected from adults in the Russian cities of Apatity and Umba (Kola Peninsula) and the Norwegian city of Tromso, all of which are locations without nearby point sources of nickel. Altogether 2,233 urine specimens were analysed for nickel. People living in Nikel had the highest concentrations (median 3.4 microg/l), followed by Umba (median 2.7 microg/l), Zapolyarny (median 2.0 microg/l), Apatity (median 1.9 microg/l), Tromso (median 1.2 microg/l), and Sor-Varanger (median 0.6 microg/l). Regardless of geographical location, the Russian study groups all had a higher urinary-nickel average than those in Norway (p<0.001). With the exception of Nikel, neither the Russian nor the Norwegian urinary-nickel levels were associated with residence location near a Russian nickel refinery. We concluded that industrial nickel pollution alone could not explain the observed discrepancy between Norway and Russia; we also discuss other possible nickel exposure sources that may account for the high urinary levels found in Russia.

Adolescent↗

PubMed1997

Prevalence of hemochromatosis among first-time and repeat blood donors in Norway.

BACKGROUND/AIMS: The observed prevalence of hemochromatosis has ranged considerably from 0.05 to 0.37% in studies requiring liver biopsy. We aimed to study the prevalence of genetic hemochromatosis among Norwegian blood donors. METHODS: We studied 10,552 healthy blood donors (5312 women and 5240 men) using serum ferritin as a screening parameter. If serum ferritin concentration was > or = 100 micrograms/l in women and > or = 200 micrograms/l in men, serum iron and transferrin (measured as total iron binding capacity = TIBC) were measured. Blood donors who repeatedly had a transferrin saturation above 40% and a ferritin concentration above these limits were referred to a hepatologist (H.B.). RESULTS: Serum ferritin was > or = 100 micrograms/l in 94/5312 (1.8%) women and > or = 200 microliters in 79/5240 (1.5%) men. Of these, 37 persons had a serum ferritin concentration above 100 micrograms/l (females) or above 200 micrograms/l (males) and a transferrin saturation above 40%. Nineteen of them (13 men and 6 women, median age 36 years, range 28-68) were identified as having hemochromatosis on the basis of increased hepatic iron index. Serum ferritin ranged from 111 to 1980 micrograms/l (median 357 micrograms/l and transferrin saturation from 50 to 100% (median 92%), hepatic iron from 48 to 471 mumol/g dry weight (median 118 mumol/g) and hepatic iron index from 1.5 to 12.1 (median 3.0). One person had cirrhosis and none had diabetes. The prevalence of hemochromatosis was significantly higher among first-time blood donors (12 out of 3500 [3.4/1000]) compared with repeat donors (7 out of 7052 [1/1000]), p < 0.005. CONCLUSIONS: The observed prevalence of hemochromatosis in Norwegian first-time blood donors of 0.34% is comparable to recently observed prevalences in other studies. However, the use of serum ferritin as a first-step screening tool may have failed to detect hemochromatosis in the early stage where iron overload has not yet occurred.

Adolescent↗

PubMed1996

Sample collection guidelines for trace elements in blood and urine. IUPAC Commission of Toxicology.

This paper presents an organized system for element-specific sample collection and handling of human blood (whole blood, serum or plasma, packed cells or erythrocytes) and urine also indicating a proper definition of the subject and sample. Harmonized procedures for collection, preparation, analysis and quality control are suggested. The aim is to assist scientists worldwide to produce comparable data which will be useful on a regional, national and international scale. The guidelines are directed to the elements aluminium, arsenic, cadmium, chromium, cobalt, copper, lead, lithium, manganese, mercury, nickel, selenium and zinc. These include the most important elements measured for their occupational or clinical significance, and serve as examples of principles that will guide development of methods for other elements in the future.

Blood Specimen Collection↗

PubMed1996

Preliminary report of trace elements in mothers and newborns living in the Kola Peninsula and Arkhangelsk region of Russia compared to Norwegian populations.

Recently, considerable attention has been allotted to the possible health effects of the industrial pollution in the regions adjoining the Norwegian-Russian border. As a measure of general health, the status of trace elements and some clinical-chemical parameters in serum and blood that reflect general health was assessed for 50 consecutive obstetric patients presenting at delivery departments of local hospitals in the Kola Peninsula, Arkhangelsk and selected centres in Norway. A written questionnaire and consent form were completed by each participant. Specimens of maternal and cord blood were collected. Corresponding samples were analyzed for copper, zinc, selenium, iron and ferritin. We found a lower birth weight in the Russian centres. The measurement of trace elements showed a higher iron status for the Russian females and relatively low serum zinc levels were observed in both the Russian and the Norwegian communities. It may be concluded that with the exception of zinc, the mineral status in the Norwegian and Russian arctic centres considered appears to be satisfactory.

Arctic Regions↗

PubMed1995

A method for establishing tentative occupational exposure limits for inhalable dust.

Four-fold classification tables are used on five datasets containing 112 parallel personal measurements of total dust and inhalable dust. The classification are carried out in such a way that the frequency of non-compliance is equal for total dust and inhalable dust. The results can be used as tentative occupational exposure limits (OELs) for inhalable dust, and the results range from 0.7 to 3.4 of OELs for total dust. The results depend on the industry and the content of the dust.

Dust↗

PubMed1995

Hepatic retention of copper and selenium in primary sclerosing cholangitis.

BACKGROUND: Previous studies have suggested abnormal copper metabolism in patients with primary sclerosing cholangitis (PSC). In the present work the trace element metabolism was studied in a group of 32 patients with PSC. METHODS: Hepatic copper and selenium concentrations were determined with a sensitive electrothermal atomic absorption technique. Serum concentrations of copper and zinc were determined by conventional atomic absorption. RESULTS: For the patient group serum copper values (20.3 +/- 4.5 mumol/l) were higher than those for the control group (14 +/- 3 mumol/l), and average hepatic copper concentrations were greater by a factor of four. Serum selenium values were slightly lower, although the average hepatic selenium was significantly higher than in the healthy control group. Previous studies have discussed possible toxic effects of hepatocellular copper accumulation, which may be accompanied by formation of activated oxygen species and depletion of glutathione. In the present study, however, it could not be demonstrated that the concentration of the lipoperoxidation product, malonic dialdehyde, was higher than normal in blood. Furthermore, blood concentrations of glutathione and glutathione peroxidase were not abnormal. CONCLUSION: Although a protective effect of the raised selenium concentrations in the liver might be discussed, it is apparent that the copper accumulation in the liver cells described here did not induce detectable changes in the indices studied.

Adolescent↗

PubMed1994

Neuropsychological deficit among elderly workers in aluminum production.

A cross-sectional study was conducted at a Norwegian primary aluminum plant. All workers aged 61-66 years were offered early retirement benefits. Among the workers, 47 met the study criteria and 38 (81%), comprising 14 potroom workers, 8 foundry workers, and 16 controls, volunteered to participate. They were tested with a neuropsychological test battery. Workers in potrooms with Søderberg electrolytic cells were found to show signs of impairment of the nervous system. A test for tremor discriminated significantly between the potroom group and the controls. There was a suggestion of increased risk of impaired visuospatial organization and a tendency to a decline in psychomotor tempo in the potroom workers. We suggest that the above findings may be related to long-term occupational exposure in the potroom, and further to chronic low-dose exposure to aluminum.

Aged↗

PubMed1994

Seminal plasma lead, cadmium and zinc in relation to tobacco consumption.

The total quantity of zinc in the ejaculates of smokers was significantly lower than in non-smokers. This was not related to a significant increase in the quantities of seminal cadmium or lead, or to a decrease in sperm quality in the smoking group. It appears that tobacco consumption may have to exceed 20 cigarettes/day before a noticeable increase in seminal cadmium can be recorded. It is suggested that this reduction in zinc secretion may jeopardize the content of chromatin zinc, and thereby the stability of the sperm chromatin. This may then contribute to reproductive failure or have consequences for fetal development.

Adult↗

PubMed1993

Small airways function in aluminium and stainless steel welders.

The effect of welding fumes on small airways was studied in 25 male subjects who welded in aluminium (Al) and to some extent also in stainless steel (SS). Despite a low exposure to welding fumes as compared to the permissible exposure limits, excretion of Al in urine was found to be increased in all subjects (median value: 0.29 mmol/mol creatinine on Friday afternoon, as compared to an upper reference level of 0.10 mmol/mol creatinine). In addition, the welders displayed increased prevalences of work-related eye and airways (pharyngitis and non-specific bronchial hyperreactivity) symptoms, as compared to 25 matched controls. Short-term welders (< or = 2.5 years) had more symptoms related to the upper airways than did long-term welders, which may indicate a selection. Spirometry, closing volume and volume of trapped gas (VTG) did not deviate. However, after methacholine inhalation, the long-term welders had a significantly steeper slope of the alveolar plateau on the single-breath nitrogen wash-out test, and a slight increase in VTG, as compared to the short-term welders and the controls. These findings may indicate a welding fume-induced increase in the reactivity of the small airways. Because Al welding was far more frequent than SS welding, an association with the former seems likely.

Adult↗

PubMed1993

A comparative study of serum selenium and vitamin E levels in a population of male risk drinkers and abstainers. A population-based matched-pair study.

Depressed selenium and Vitamin E levels may contribute to hepatic injury through lipid peroxidation. To study the effect of moderate alcohol drinking (32.4 +/- 23.6 g ethanol/d) on serum selenium and serum vitamin E concentrations, we conducted a matched-pair study of 73 healthy, well-nourished risk drinkers and healthy controls with little or no alcohol consumption. Among risk drinkers, serum selenium was significantly lowered (1.49 vs 1.67 mumol/L; p < 0.001) compared with controls. Difference in alpha-tocopherol concentrations did not, however, reach statistical significance (22.8 vs 24.9 mumol/L; p = 0.06). Nutritional and life-style factors differed very little between the two groups. We conclude that even moderate alcohol consumption lowers selenium status. Selenium may thus represent a link joining the hepatotoxic and nutritional backgrounds of alcoholic liver disease.

Adult↗

PubMed1993

Mercury and selenium in workers previously exposed to mercury vapour at a chloralkali plant.

The concentrations of total mercury (B-Hg), inorganic mercury (B-IHg), and methyl mercury (B-MeHg) in whole blood, urinary mercury (U-Hg), and selenium in urine (U-Se) and whole blood (B-Se) were determined in 74 chloralkali workers previously exposed to Hg vapour, and compared with 51 age matched referents. Dental amalgam state, fish consumption, and exposure related indices were studied with regard to the determined elements. A significant relation between the surface of dental amalgam and U-Hg (Pearson's r = 0.63, p < 0.001) was found among the referents. Mean U-Se was significantly lower (p < 0.001) among the subjects previously exposed to Hg (34.1 nmol/mmol creatinine) compared with that for the referents (42.6 nmol/mmol creatinine). A significant negative relation between the cumulative Hg dose and U-Se was also found. The mechanisms and the clinical significance of these findings are not clear. No relation between current U-Hg and previous occupational exposure to Hg was found among subjects in whom exposure had ceased more than one year before the study.

Adult↗

PubMed1993

Concentrations of lead, cadmium and zinc in the tissues of reproductive organs of men.

The concentrations of lead in blood and the concentrations of lead, cadmium and zinc in tissues were determined in various reproductive organs, liver and kidney removed at necropsy from 41 men who had died suddenly. None of the reproductive organs specifically accumulated lead and no significant correlation could be demonstrated between blood and organ concentrations or between concentrations and age, occupation or urban/rural background of the subject. Unlike lead, the tissue concentrations of cadmium increased with increasing age in all of the reproductive organs examined. Of these, the epididymides and seminal vesicles contained the highest concentrations. Whereas prostatic zinc also exhibited a significant age-dependent increase, the concentrations in the testes declined with age. The age-dependent increase in testicular cadmium did not become apparent until after the fourth decade, when any potentially deleterious impact on male fertility has less relevance. It is concluded that measurable amounts of lead and cadmium are present in all of the human reproductive organs but their organ and age distribution do not offer strong support for their involvement in the aetiology of male infertility or in the genesis of glandular neoplasms.

Adolescent↗

PubMed1993

Serum selenium, copper, and zinc concentrations in Crohn's disease and ulcerative colitis.

Serum selenium, copper, and zinc levels were studied in 47 patients with Crohn's disease, 117 patients with ulcerative colitis, and 123 age- and sex-matched healthy controls. Serum selenium levels were lower and serum copper levels were higher in men and women with Crohn's disease than in controls (p < 0.001 and p < 0.01, respectively). Trace element levels were not significantly influenced by extent or localization of Crohn's disease. Men and women with ulcerative colitis had higher levels of copper and zinc than did controls (p < 0.01 and p < 0.05, respectively). Men with pancolitis had significantly lower selenium and higher copper levels than men with proctitis. The implications of abnormal trace element status in patients with inflammatory bowel disease are discussed.

Adult↗