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Biomedical subjects

G Sällsten

Publications and source records attributed to G Sällsten.

At least 37 records · Page 2Linked to original sources
PubMed1994

Clearance half life of mercury in urine after the cessation of long term occupational exposure: influence of a chelating agent (DMPS) on excretion of mercury in urine.

The elimination of mercury (Hg) in urine was investigated in 12 former chloro-alkali workers exposed to metallic Hg vapour for two to 18 (median five) years. Morning urine samples were taken on several (median 9) occasions after change of employment or retirement. The median follow up time was 28 months. The decrease in concentration of Hg in urine (U-Hg) was well characterised by a one compartment model. Three different regression methods were used; non-linear least squares regression (NLSR), weighted non-linear least squares regression (WNLSR), and linear least squares regression (LLSR) after log transformation of the U-Hg data. The median half life from the WNLSR method was 55 days. There were no large differences in the half life estimates given by the WNLSR or the NLSR methods, but for five subjects the LLSR method gave poor fits. There was a non-significant tendency towards longer half lives with higher initial U-Hg. About three years after the cessation of occupational exposure a mobilisation test with 2,3-dimercaptopropane-1-sulphonate (DMPS) was performed on seven subjects. Excretion of Hg, copper (Cu), and zinc (Zn) in urine was estimated before and after the ingestion of 300 mg of DMPS. Treatment with DMPS increased 24 hour urinary excretion by a factor of 7.6 for Hg, 12 for Cu, and 1.5 for Zn. The relative increase in U-Hg was not significantly higher than that obtained in a previous study of an occupationally unexposed group. A major proportion (62%) of Hg excreted during 24 hours after DMPS appeared in the first six hours.

Adult↗
PubMed1994

Endocrine function in mercury exposed chloralkali workers.

OBJECTIVE: The aim was to study whether functional impairment of the pituitary, thyroid, testes, and adrenal glands of humans occupationally exposed to mercury (Hg) vapour can be shown as a result of accumulation of Hg in these glands. METHODS: Basal concentrations of thyrotrophin (TSH), prolactin, free thyroxine (free T4), free 3,5,3'-triiodothyronine (free T3), antibodies against thyroperoxidase, and testosterone in serum, as well as cortisol in morning urine were measured in 41 chloralkali workers exposed (10 years on average) to Hg vapour, and in 41 age matched occupationally unexposed referents. The chloralkali workers had a mean urinary Hg concentration (U-Hg) of 15 nmol/mmol (27 micrograms/g) creatinine, and a mean blood Hg concentration (B-Hg) of 46 nmol/l. For the reference group U-Hg and B-Hg were 1.9 nmol/mmol (3.3 micrograms/g) creatinine and 17 nmol/l respectively. RESULTS: The serum free T4 concentration and the ratio free T4/free T3 were slightly, but significantly, higher in the subgroups with the highest exposure, and the serum free T3 was inversely associated with cumulative Hg exposure. This indicates a possible inhibitory effect of mercury on 5'-deiodinases, which are responsible for the conversion of T4 to the active hormone T3. Serum total testosterone, but not free testosterone, was positively correlated with cumulative Hg exposure. Prolactin, TSH and urinary cortisol concentrations were not significantly associated to exposure. CONCLUSION: Apart from inhibition of the deiodination of T4 to T3, the endocrine functions studied seem not to be affected by exposure to Hg vapour at the exposure levels of the present study. Growth hormone secretion was not studied.

Adrenal Glands↗
PubMed1993

Decrease in mercury concentration in blood after long term exposure: a kinetic study of chloralkali workers.

The elimination of mercury (Hg) in blood was investigated in 14 chloralkali workers exposed to metallic Hg vapour for 1-24 (median 10) years. Blood and urine samples were collected on several (median eight) occasions during a period of 17-26 days. The initial Hg concentrations were about 80 nmol/l in whole blood (B-Hg) and 17 nmol/mmol creatinine in urine (U-Hg). The decrease in Hg in whole blood, plasma (P) and erythrocytes (Ery) was best characterised by a two compartment model. In a model with a common half life for all subjects, the best fit for B-Hg was obtained with half lives of 3.8 days for a fast phase and 45 days for a slow phase. The half life of the fast phase was shorter for P-Hg than for Ery-Hg, whereas the opposite was the case for the slow phase. The half lives of the slow phases in whole blood and plasma were longer, and the relative fractions of the slow phases were higher (about 50%) after long term exposure than those (about 20%) reported after brief exposure. Slower elimination indicates higher accumulation of Hg in organs with long half lives, and possibly the presence of at least one additional, even slower compartment. The U-Hg fluctuated substantially during the sampling period, and average concentrations decreased only slightly.

Adult↗
PubMed1991

Mortality from asthma, chronic obstructive pulmonary disease, respiratory system cancer, and stomach cancer among paper mill workers: a case-referent study.

In an earlier case-referent study from a soft-paper mill with levels of paper dust exceeding 5 mg/m3, an increased mortality was found (OR = 3.8, p less than 0.05) from asthma and chronic obstructive pulmonary disease (COPD) among the employed. Furthermore, other studies on paper mill workers have also indicated an increased mortality from lung cancer. The main objectives of the present case-referent study were to investigate the mortality from asthma. COPD, and lung cancer in two other Swedish paper mills. In these mills, the levels of paper dust have been below 3 mg/m3. The subjects for the study were all men who died between 1961 and 1985 from asthma and COPD (n = 31), respiratory cancer (n = 27), and stomach cancer (n = 33) selected in three parishes surrounding two paper mills. As referents we randomly selected about six times as many men who had died from nonmalignant nonrespiratory diseases in these parishes (n = 550). On the basis of information found in the personnel records in the mills, the men were classified into different occupational categories or as unexposed. No increased risk of asthma or COPD was found among the workers exposed to paper dust. However, it was found that there was significantly increased mortality (OR = 5.7, p less than 0.05) for asthma and COPD among workers in a previous log sorting department. The study also showed a significantly increased risk of lung cancer (OR = 2.1, p less than 0.05) among maintenance workers. There was no increased risk of stomach cancer in the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Mobilized mercury in subjects with varying exposure to elemental mercury vapour.

In a mercury mobilization test, 0.3 g of the complexing agent sodium 2,3-dimercaptopropane-1-sulfonate (DMPS) was given orally to 10 workers with moderate occupational exposure to elemental mercury vapour, to 8 dentists with slight exposure, to 18 matched controls, and to 5 referents without amalgam fillings. In the workers, DMPS caused an increase in 24-h urinary mercury excretion by a factor of 10; in the dentists, 5.9; in the controls, 5.3; and in the amalgam-free referents, 3.8. Of the mercury excreted during 24 h, 59% appeared during the first 6 h. Close, albeit non-linear, associations were found between mobilized mercury and the premobilization mercury levels in plasma and urine, but not with the duration of occupational exposure or the rough estimate of the integrated function of blood levels vs time. The present data indicate that mercury mobilized after a single DMPS dose in close connection with exposure is mainly an index of recent exposure and is not significantly affected by slow body pools or long-term exposure.

Adult↗
PubMed1991

Effects of occupational exposure to mercury vapor on lymphocyte micronuclei.

For 26 chloralkali workers exposed to inorganic mercury and 26 age-matched, occupationally unexposed referents, the frequency and size distribution of micronuclei were determined in peripheral lymphocytes stimulated with either phytohemagglutinin or pokeweed mitogen. For the exposed workers the mean concentrations of mercury in urine, plasma, and erythrocytes were 16 nmol/mmol of creatinine, 48 nmol/l, and 78 nmol/l, respectively, and their mean exposure time was 10 years. Neither the frequency nor the size of micronuclei was significantly different in the two groups; nor were there any correlations to current mercury levels. However, in the exposed group, and with phytohemagglutinin as the mitogen, a statistically significant correlation between previous exposure to mercury (cumulative exposure or number of blood mercury peaks) and the frequency of micronuclei was found. This association was also present when the effects of age and smoking were allowed for, and it may indicate an accumulation of cytogenetic effects in T-lymphocytes.

Adult↗
PubMed1991

Polyneuropathy possibly caused by 30 years of low exposure to n-hexane.

A slowly developing, mainly sensory, polyneuropathy was found in a 60-year-old man exposed to n-hexane (10-100 mg/m3) for 30 years in a mountain fuel stockpile. The nerve damage was verified by electromyography and sural nerve biopsy, and it is proposed that also a low-grade, but prolonged, exposure to n-hexane may cause polyneuropathy.

Biopsy↗
PubMed1990

Characterization of airborne dust in a soft paper mill.

The characteristics of airborne dust in a soft paper production plant have been characterized by scanning and transmission electron microscopy. A combination of X-ray diffraction, electron diffraction and energy-dispersive X-ray flouresence spectroscopy (EDX) was used to determine the structure and composition of the different components. Size distribution determination and phase identification were carried out. Besides the cellulose fibres, fibres of kaolinite, wollastonite, talc and other silicates were also identified. Gravimetric analysis and fibre counting by optical phase contrast microscopy were used to determine total dust and fibre concentrations. Total dust exposure at the plant was generally below 3 mg m-3. The respirable fraction of the total dust concentrations varied from 15 to 70%. The inorganic dust was 36 +/- 15% of the total dust. The ratio of inorganic fibres to total fibre concentration at the plant varied between 10 and 15%.

Air Pollutants, Occupational↗
PubMed1990

Mercury in the Swedish chloralkali industry--an evaluation of the exposure and preventive measures over 40 years.

The monitoring of exposure to mercury in the Swedish chloralkali industry started in 1946 and became common in the 1960s. During the 1970s both urinary and blood mercury (U-Hg, B-Hg) concentrations decreased substantially. The mean (geometric) U-Hg was 500-700 nmol l.-1 in the 1960s as compared with 150 nmol l.-1 today. During the 1970s the mean (geometric) B-Hg declined from about 100 to 40 nmol l.-1. Nowadays high values, U-Hg greater than 1500 nmol l.-1 or B-Hg greater than 600 nmol l.-1, are very rare whereas in the 1950s and the 1960s such peak values were found among 30% of the workers. The most effective measures taken were the reduction of the hydrogen discharges from the process and the replacement of graphite anodes by dimensionally stable anodes which require less frequent maintenance. Today efficient cleaning and continuous monitoring make it possible to keep the exposure levels low. The use of respiratory protection equipment is, however, still necessary during certain maintenance operations.

Air Pollutants↗
PubMed1990

Cerebrospinal fluid proteins in men with chronic encephalopathy after exposure to organic solvents.

Cerebrospinal fluid was examined for 23 patients with chronic toxic encephalopathy after heavy exposure to organic solvents and 23 healthy age-matched referents. No differences were found between the patients and referents with respect to the levels of albumin, immunoglobulin, prealbumin, alpha-1-antitrypsin, beta-2-microglobulin, haptoglobin, or the astroglial cell proteins S100 and glial fibrillary acidic protein in the cerebrospinal fluid. The albumin ratio was normal for both the patients and the referents. The patient group had had heavy exposure to organic solvents, but its members had not been exposed for at least one year before the study. It was concluded that, if exposure to organic solvents affects proteins in cerebrospinal fluid, such effects are probably reversible.

Adult↗
PubMed1990

Mortality and cancer incidence in chloralkali workers exposed to inorganic mercury.

Mortality and cancer incidence were studied in men exposed to inorganic mercury at eight Swedish chloralkali plants where individual biological monitoring data were available. Urinary mercury excretion has declined from about 200 micrograms/l during the 1950s to less than 50 micrograms/l today. These workers had also been exposed to chlorine and static magnetic fields. At some of the plants there had been a low degree of exposure to asbestos. In total, 1190 men had been monitored for at least one year between 1946 and 1984. Their mortality and cancer incidence were compared with those of the general male population. Mortality from all causes was not significantly increased (rate ratio = 1.1). Cardiovascular mortality was slightly increased (rate ratio = 1.3; 95% CI 1.0-1.5) for no known reason. An excess of lung tumours was seen (rate ratio = 2.0; 95% CI 1.0-3.8), possibly caused by previous exposure to asbestos. Mortality from non-malignant diseases of the brain and the kidneys, the main target organs in mercury poisoning, was not increased, nor was the incidence of brain tumours (3 observed v 1.1 expected) or kidney tumours (3 observed v 1.9 expected).

Aged↗
PubMed1989

Lung function and respiratory symptoms among workers in a soft paper mill.

The aim of the present cross-sectional study was to investigate whether long-term exposure to soft paper dust causes impairment of lung function. Exposed workers (n = 287) and referents (n = 79) were investigated, using spirometry and questionnaires. Personal samplings of total dust showed that the actual mean concentrations did not exceed 3 mg/m3. The exposed subjects were divided into three categories according to historical and present exposure to paper dust; low exposure, moderate exposure and high exposure. The study did not show any lung function impairment due to exposure to paper dust. However, the exposed subjects had a significantly increased prevalence of symptoms from both the upper and lower airways as well as an increased prevalence of reported asthma. On the basis of our study, we conclude that lung function impairment does not occur among workers exposed to mean levels of soft paper dust below 5 mg/m3.

Cross-Sectional Studies↗
PubMed1988

Pleural mesotheliomas and asbestos exposure in the pulp and paper industries: a new risk group identified by linkage of official registers.

Analysis of data obtained by linking the 1960 Swedish Census and the Swedish Cancer Registry has demonstrated an increased risk of pleural mesothelioma among pulp and paper workers. The present study was undertaken with the aim of revealing possible environmental risk factors. The work histories of the 25 cases identified earlier were reviewed. "Certain" or "probable" exposure to asbestos was found among 70% of these workers. The study illustrates how linkage of official registers can be used to identify new risk environments and encourage the establishment of preventive measures.

Asbestos↗
PubMed1988

Enzymuria in workers exposed to inorganic mercury.

Urinary excretion of beta-hexosaminidase (NAG = N-acetyl-beta-glucosaminidase) and albumin was examined in 41 chlor-alkali workers exposed to inorganic mercury and 41 age-matched controls. Either U-HG or B-Hg levels for these workers were available dating from the 1960s to the present. Increased U-NAG was seen in workers with a U-Hg today of more than 4 micrograms/mmol creat (about 50 micrograms/l: 35 ug/g creat). Multiple linear regression analysis showed that U-NAG was correlated to U-Hg and integrated dose but not to the present B-Hg level. No albuminuria (detection limit 12.5 mg/l) was found in any of the subjects. In a longitudinal study, no decrease in U-NAG levels was seen in 15 chlor-alkali workers after their vacation (means = 20d). In five workers followed for ten months after a short exposure period, no definite time trend could be seen. The results show that there is a slight effect on renal tubules even at rather low levels of exposure to mercury vapour. The clinical significance of the enzymuria levels found here is, however, debatable.

Acetylglucosaminidase↗
PubMed1986

Chronic and acute effects of solvents on central nervous system functions in floorlayers.

Floorlayers and age matched carpenters with long (greater than or equal to 20 years) and short (5-10 years) occupational experience were compared with respect to chronic and acute neuropsychiatric, neuropsychological, and general health effects as related to different types of solvent exposure. An increased prevalence of neuropsychiatric illness occurred among floorlayers with long occupational experience, possibly caused by high levels of exposure which were present until the 1970s. The disease appears partly reversible since, at the time of the investigation, all had essentially recovered. Some impairment of performance in psychological tests was seen, however, in this group. Visuoanalytical impairment was associated with indices of exposure to glues based on alcohols whereas contact adhesives appeared more deleterious to perceptual functions. The increased prevalence of neuropsychiatric symptoms among the floorlayers was interpreted to reflect mainly acute effects on the central nervous system.

Acute Disease↗