Biomedical subjects
I Lundberg
Publications and source records attributed to I Lundberg.
[Hypokalemic paralysis in Sjögren's syndrome].
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Three industrial solvents investigated for tumor promoting activity in the rat liver.
Dioxane, perchloroethylene, and trichloroethylene were investigated as rat liver altered foci promoters in an initiation/promotion protocol. Animals were initiated with diethylnitrosamine, 30 mg/kg, injected i.p. 24 h after 2/3 partial hepatectomy. The chemical under study was administered by gavage once a day, 5 times a week for 7 weeks. Ten days after the last administration the animals were killed. Liver sections were stained for gamma-glutamyl-transpeptidase (GGT) and the number and total volume of GGT-positive foci was studied. Dioxane (1000 mg/kg) significantly increased the number and total volume of foci while a marginal effect was noted for the high dose of trichloroethylene (1100 mg/kg). A high dose of perchloroethylene (1100 mg/kg) had no effect.
Visual constraints in reading: evidence from non-ocular behaviour.
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Relative hepatotoxicity of some industrial solvents after intraperitoneal injection or inhalation exposure in rats.
Intraperitoneal LD50 (lethal dose 50% kill) values and minimal liver toxic doses in female Sprague-Dawley rats were determined for the following industrial solvents: toluene, methylene chloride, carbon tetrachloride, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, ethanol, methyl ethyl ketone, and dioxane. For the following solvents LC50 values and minimal liver toxic air concentrations were also determined: xylene, styrene, chloroform, tetrachloroethylene, and dimethylformamide (DMF). The serum activity of the enzyme sorbitol dehydrogenase (SDH) was used as an indicator of liver damage. Carbon tetrachloride, chloroform, and DMF were hepatotoxic in low doses compared to LD50 values (TD50 (toxic dose 50%) values approximately 30, 90, and 50 mg/kg). Chloroform and DMF were hepatotoxic in comparatively low concentrations after a 4-hr inhalation exposure (TC50 (toxic concentration 50%) values approximately 590 and 740 mg/m3). Even relatively high doses of the other solvents did not raise the SDH activity. Significant direct (metabolite-mediated) hepatotoxicity seems to be an uncommon feature among commonly used industrial solvents.
Correlation of xylene exposure and methyl hippuric acid excretion in urine among paint industry workers.
Different calculations of methyl hippuric acid excretion in urine were correlated to the time-weighted average (TWA) of the xylene exposure of a complete workday for 40 paint industry workers exposed to 12 different solvents. The 8-h TWA xylene exposure varied between 0 and 865 (median 69) mg/m3. The amount of methyl hippuric acid excreted in about 24 h showed only a slightly higher linear correlation to the xylene exposure than the amount of methyl hippuric acid excreted per hour during the latter part of the workshift among the 37 subjects exposed to TWA xylene air concentrations of 0-200 mg/m3. It was concluded that the methyl hippuric acid excretion rate during the latter part of the workshift can be used for crude xylene exposure categorizations.
Mortality and cancer incidence among Swedish paint industry workers with long-term exposure to organic solvents.
Cause-specific mortality was studied in a cohort of 416 men who had worked for at least five years in the Swedish paint manufacturing industry during the period 1955-1975. The calculations of expected numbers were based on national, male, calendar-year, and cause-specific death rates for the period 1961-1981. Ninety-six paint industry workers had died, whereas 110 deaths were expected. Three workers had died from multiple myeloma (0.6 expected), and the excess might be related to solvent exposure. Three cleaners had died from infectious urinary tract disease, in comparison to 0.2 deaths expected from all genitourinary diseases, in this small and very heavily exposed group. This association might possibly indicate a modifying effect on the prognosis of urinary tract morbidity from solvents.
Normal serum activities of liver enzymes in Swedish paint industry workers with heavy exposure to organic solvents.
The serum activities of the liver enzymes alanine aminotransferase, aspartate aminotransferase, ornithine carbamyl transferase, and gamma-glutamyl transferase were examined in 47 paint industry workers and unexposed age matched referents. The workers were exposed to a mixture of industrial solvents, of which xylene was the main component in most cases. The median total exposure was about 50% of Swedish 1981 threshold limit values according to measurements of individual solvent exposure performed at the same time. No differences in enzyme activities were shown either when the whole exposed and referent groups were compared or when the five workers with outstanding solvent exposures of five times the TLV or more were compared with their referents. It is concluded that in most workers the liver seems to remain largely undamaged from inhalation exposure to a commonly used mixture of non-chlorinated solvents. In many workers this seems to hold true even for high exposures for limited periods.
Environmental factors and uptake of cadmium among brazers using cadmium-containing hard solders.
The influence of different work factors on the uptake of cadmium has been studied in 102 brazers working at least 10% of their work day with cadmium-containing hard solders. The blood concentrations of cadmium varied between less than 1 and 113 micrograms/L (less than 9 and 1010 nmol/L). Blood cadmium concentrations were below 10 micrograms/L (89 nmol/L) in 71 brazers and 31 brazers had levels equal to or above that value. The importance of some environmental factors on the blood-level of cadmium was studied with discrimination analysis. The length of the splice was found to be almost the sole determining factor for the cadmium concentration in blood. All brazers working with splices shorter than 2 cm had blood concentrations below 10 micrograms/L, while 87% of the brazers working with splices longer than 10 cm had blood concentrations equal to or above 10 micrograms/L. Other factors like age, sex, exposure time, smoking habit and brazing method were devoid of any measurable importance.
Delayed dimethylformamide biotransformation after high exposures in rats.
Rats were exposed to two dimethylformamide (DMF) air concentrations (2250 and 565 ppm for 4 h). Concentrations of DMF and the biotransformation product monomethylformamide (MMF) were measured in blood and some tissues at different times after the end of exposure. MMF concentrations 0 and 3 h after the end of the high exposure were generally lower than MMF concentrations at the same time after the low exposure. The results suggest that DMF biotransformation to MMF is delayed after the high exposure. As the hepatotoxic effect of DMF has been correlated with MMF, this could contribute to the previously observed slower appearance of hepatotoxicity after a high compared to a low DMF dose.
Can phonemic awareness be trained in kindergarten?
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Aluminium in the blood and urine of industrially exposed workers.
Blood and urine aluminium concentrations were studied in industrially exposed workers using electrothermal atomic absorption spectrometry. Welders and workers making aluminium powder and aluminium sulphate had higher concentrations in blood and urine than non-exposed referents. Workers in the electrolytic production of aluminium had higher urine but not blood concentrations than the referents. Thus aluminium was found to be absorbed by all industrially exposed workers. Blood concentrations were lower than those presumably associated with aluminium induced encephalopathy in patients receiving dialysis.
Some observations on dimethylformamide hepatotoxicity.
Dimethylformamide (DMF) and its biotransformation products monomethylformamide (MMF) and formamide (F) were administered intraperitoneally to rats. Serum levels of sorbitol dehydrogenase (SDH) were studied at 3 h intervals from 9 h to 30 h after administration. Liver histology at 12, 21 and 30 h proved elevated SDH levels to be an indication of liver necrosis. DMF 479 mg/kg produced elevated enzyme levels at 27 h and 30 h while half the dose, 240 mg/kg, produced elevated levels from 15 h onwards. MMF 387 mg/kg produced elevated SDH levels at all times studied. F did not give elevated levels at any time. DMF (479 mg/kg) and MMF (387 mg/kg) administered simultaneously produced elevated SDH levels from 24 h onwards. These findings suggest that DMF hepatotoxicity is mediated by a degradation product of MMF and that DMF delays the hepatotoxic effect induced by MMF.
Studies on kidney function in subjects exposed to organic solvents. I. Excretion of albumin and beta-2-microglobulin in the urine.
The urine of 134 subjects, exposed to different organic solvents, and 48 unexposed subjects has been analysed with reference to albumin and beta-2-microglobulin excretion. The exposed subjects excreted significantly larger quantities of albumin than the unexposed. Those exposed to styrene excreted the largest amounts. No significant difference in beta-microglobulin excretion could be demonstrated between the groups.
Chromosome aberrations and sister chromatid exchanges in Swedish paint industry workers.
Workers in the Swedish paint industry exposed to a mixture of organic solvents, mainly containing xylene or toluene, were investigated for genotoxic effects. No difference in the frequency of sister chromatid exchanges (SCE), 0.192 and 0.193 per chromosome, respectively, was noted in the peripheral lymphocytes of the exposed group of 17 workers and their matched reference group. No correlation was found between xylene or toluene exposure and SCE frequency nor between total solvent exposure and SCE frequency. The frequency of chromosome aberrations was also investigated for the five most exposed workers and their matched referents, and no difference was found. There was no correlation between SCE and chromosome breaks.
On the morphology of live spermatozoa of human semen.
Live and dead spermatozoa of human semen were distinguished and evaluated separately with respect to their morphology after supravital staining with buffered eosin. This evaluation was shown to be almost as reliable as that of the commonly stained smear. Different samples from the same individual were found to be similar with respect to both the total population and the live population. Different types of abnormalities were not equally common in the live and dead populations. Tapered heads were more common in the live population and abnormal midpieces more common in the dead, whereas abnormal tails and cytoplasmic droplets occurred with the same frequency in both populations. However, neither the frequency of all spermatozoal abnormalities nor that of abnormal heads or midpieces studied separately showed strong correlations in the two populations, in contrast to the frequencies of tapered heads, cytoplasmic droplets, and abnormal tails. No constant relationship was found between the live population and the entire sperm population with respect to numerical differences or quotients between the figures for abnormal cell frequency.Therefore, study of the morphology of the live sperm population gives supplementary information about the qualities of semen not attained by previous methods of study.
Primary antibody response by chicken spleen cells in vitro.
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The prevalence of reading and spelling difficulties among inmates of institutions for compulsory care of juvenile delinquents.
Recent studies have focused on reading and writing disabilities among inmates in prisons and at juvenile institutions. Some studies in Sweden have demonstrated that more than half of the delinquents have serious reading difficulties, and for immigrants the situation is even worse. However, these studies have focused on small groups. Furthermore, little attention has been paid to different types of reading and writing difficulties. The main purpose of this investigation was to estimate the prevalence of reading and writing disabilities in juvenile institutions. The study analyses gender differences and differences between immigrants and Swedish pupils. The study included 163 pupils from 22 institutions and used three tests of literacy skills: word identification, spelling and reading comprehension. More than 70% showed some problems in reading and spelling. However, only 11% had serious difficulties. Moreover, the results showed that comprehension ability among immigrant boys was lower than among Swedish boys, despite the same level of word reading skill. The high prevalence of reading and writing disabilities seems primarily to be related to social and cultural factors, home backgrounds, limited school attendance and poor self-esteem rather than to constitutional problems of a dyslexic nature. The implication of this conclusion may be important for the intervention process.