Search tips
Search criteria

Results 1-25 (67)

Clipboard (0)
Year of Publication
Document Types
5.  Leptospira hebdomadis associated with an outbreak of illness in workers on a farm in North Yorkshire. 
Four cases of illness attributed to Leptospira hebdomadis occurred on a cattle farm in North Yorkshire. The clinical features were a febrile illness that resembled influenza; in one case there was a lymphocytic meningitis. This infection is probably more common than is recognised at present, and prevention of further cases may be possible if diagnosed promptly.
PMCID: PMC1008759  PMID: 7448136
6.  Retention of vinyl chloride in the human lung. 
Experiments with volunteers showed that 42% of an inhaled dose of vinyl chloride is retained in the lungs. This value is independent of the concentration of vinyl chloride in the air. Elimination of vinyl chloride through the lungs is negligible since its concentration in expired air decreases immediately after the cessation of exposure.
PMCID: PMC1008754  PMID: 7448132
16.  Placental and stillbirth tissue lead concentrations in occupationally exposed women. 
The lead values in maternal and infant blood, in placental tissue, and in stillbirth liver, kidney, and rib- and skull-bones have been determined in samples from the Stoke-on-Trent area. The lead values in antenatal blood and placenta increase with occupational exposure; liver and kidney stillbirth lead values are lower than those of much older children and rib-bone lead values from stillbirths were on average three times as high as those from a control group comprised of cot deaths and early infant deaths from accidental causes.
PMCID: PMC1008758  PMID: 7448135
17.  Effects of chronic ethanol consumption on hepatic metabolism of aromatic and chlorinated hydrocarbons in rats. 
The activities of liver drug-metabolising enzymes for 16 aromatic or chlorinated hydrocarbons were measured in male rats after a three-week daily intake of ethanol amounting to 30% of total energy intake. Although the ethanol feeding produced only a slight increase in the microsomal cytochrome P-450 content, it increased the in-vitro metabolism of most hydrocarbons three-to six-fold. That a major part of this enhanced activity disappeared after one-day withdrawal of ethanol suggests that recent intake of ethanol plays an important part in accelerating the metabolism of hydrocarbons. The enzyme activity enhanced by ethanol was found to be related with changes occurring not in the soluble but in the microsomal fractions. A metabolism study using toluene as a model substrate indicated that chronic ethanol consumption increases the in-vivo metabolism of this hydrocarbon in rats.
PMCID: PMC1008756  PMID: 7192567
18.  Scanning electron microscopy and x-ray microanalysis of mineral deposits in lungs of a patient with pleural mesothelioma. 
Scanning electron microscopy of lung tissue, ashed at low temperature, and obtained from an insulation worker who had died of pleural mesothelioma, showed the presence of numerous inorganic particles and fibres. A regional variation in fibre concentration in different tissue samples was found, and the size distribution of naked fibres and asbestos bodies was determined. By energy dispersive x-ray microanalysis the fibres were identified mainly as amphibole asbestos. This method also showed the presence of particles containing titanium and of fragments of diatom shells. Despite a mean concentration of 33 x 10(6) fibres per gram of dry tissue no significant lung fibrosis was found.
PMCID: PMC1008755  PMID: 7448133
19.  Pulmonary disease from occupational exposure to an artificial aluminium silicate used for cat litter. 
All available workers engaged in bagging an artificial crystalline aluminium silicate--the kiln-dried residue from the calcining and water extraction of alunite (a hydrated sulphate of aluminium and potassium) that is currently classified as a nuisance dust--were studied after a complaint of respiratory and systemic symptoms, including arthritis, by an employee of the factory, who showed physiological and radiographic evidence of diffuse pulmonary fibrosis and in whom lung biopsy showed diffuse fibrosis with granulomas. Inhalation challenge produced a transient decrease in transfer factor and transfer factor standardised for alveolar volume. Twenty-five subjects were known to have been exposed at some time to the dust of alunite-residue. Of the 17 who could be contacted, all agreed to attend for respiratory questionnaire and occupational history, pulmonary function testing (spirometry, lung volumes, gas transfer), and posteroanterior chest radiograph. Six subjects considered that occupational exposure to the dust was responsible for respiratory symptoms. Three subjects had abnormality of the chest radiograph consistent with pulmonary fibrosis. The mean percentage of predicted transfer factor standardised for effective alveolar volume was 71.1% in subjects with abnormal chest radiographs and 86.6% in subjects with normal radiographs (p = 0.10). There was a trend in the correlation between the percentage of predicted transfer factor standardised for effective alveolar volume and total dust exposure (sum of the products of grade of severity of each exposure period and duration of each exposure period in months) (r = 0.40 p = 0.10). This study suggests that there may be a relation between inhalation of the dust of this form of aluminium silicate and pulmonary fibrosis.
PMCID: PMC1008753  PMID: 7448131
20.  Observations on the lungs of vanadium workers. 
Out of a total of 79 employees at a factory making vanadium pentoxide from magnetite ore 63 were investigated by respiratory questionnaire, chest radiography, and tests of ventilatory function. The findings were compared with a reference group of 63 men, matched for age (to within two years) and for smoking habit (to within five cigarettes daily) selected from workers at a magnetite ore mine. Analysis of the ventilation tests showed no significant differences between the reference group and the men exposed to low concentrations of vanadium (0.01--0.04 mg/m3), despite previous exposure for an average of 11 years to concentrations in the range of 0.1 to 3.9 mg/m3. Complaint of wheezing was significantly more common among the workers exposed to vanadium than among their referents, but there were no other subjective differences between the groups. Localized fibrotic foci were reported in the radiographs of four reference cases and two men exposed to vanadium, but there were no cases of pneumoconiosis in either group.
PMCID: PMC1008752  PMID: 7448130
21.  Epoxides--is there a human health problem? 
The purpose of this review is to consider whether epoxides represent a hazard to human health. Possible means of occupational and non-occupational exposure are discussed with reference to the production and uses of industrially important compounds and other epoxides, such as naturally occurring plant and fungal products. In addition to epoxides themselves, unsaturated compounds that may be metabolised in vivo to epoxides are included, since this appears to be a further important means of exposure. The toxicology, in particular carcinogenicity and mutagenicity, is discussed, along with a brief outline of the biochemistry such as metabolism, binding to cell constituents, and DNA repair mechanisms. The question of interactions between different epoxides in vivo is also raised.
PMCID: PMC1008750  PMID: 7004476
22.  Role of family susceptibility, occupational and family histories and individuals' blood groups in the development of silicosis. 
A previous investigation has shown that family susceptibility and occupational and family histories have a decisive role in the development of byssinosis among workers exposed to flax dust. Results of investigation of silicosis in 814 male workers exposed to silica-bearing dust showed that family susceptibility has an important role in the development of silicosis among examined workers, and workers whose fathers had an occupational history of exposure to silica-bearing dust were more resistant to the development of the disease than those with non-exposed fathers. The degree of consanguinity of parents and individuals' blood groups, also, have a role. Workers with cousin parents were relatively highly susceptible to the development of silicosis as well as workers with blood groups "O" or "AB". It has been concluded that the investigated factors might have a role in the development of other occupational diseases and further investigations are indicated.
PMCID: PMC1008760  PMID: 6255981
23.  Influence of chronic carbon disulphide intoxication on the development of experimental atherosclerosis in rats. 
Rats fed on atherogenic diets containing 2% cholesterol and 0.5% cholic acid with or without 0.15% thiouracil were exposed to carbon disulphide (CS2) vapours (1 mg/l of air), five hours a day, six days a week for 6-10 months. Serum and aorta lipid contents were determined, and the extent of atherosclerotic changes was investigated. The following effects of chronic exposure to CS2 were found: (1) slower gain in body weight when rats were fed on atherogenic diet; (2) greater increase in serum cholesterol content (after thiouracil supplemented diet); (3) moderate increase in total cholesterol content in the aorta wall with a significantly increased esterified cholesterol fraction but none in phospholipid level in this tissue; and (4) more advanced lipid infiltrates of coronary arteries and endocardium, the latter predominantly in the aortic valves. These results together with data from previous studies indicate that metabolism of arterial lipids participates in the process of artheroma formation after chronic exposure to CS2 vapours.
PMCID: PMC1008757  PMID: 7448134
24.  Deposition, retention, and clearance of inhaled particles. 
The relation between the concentrations and characteristics of air contaminants in the work place and the resultant toxic doses and potential hazards after their inhalation depends greatly on their patterns of deposition and the rates and pathways for their clearance from the deposition sites. The distribution of the deposition sites of inhaled particles is strongly dependent on their aerodynamic diameters. For normal man, inhaled non-hygroscopic particles greater than or equal to 2 micrometers that deposit in the conducting airways by impaction are concentrated on to a small fraction of the surface. Cigarette smoking and bronchitis produce a proximal shift in the deposition pattern. The major factor affecting the deposition of smaller particles is their transfer from tidal to reserve air. For particles soluble in respiratory tract fluid, systemic uptake may be relatively complete for all deposition patterns, and there may be local toxic or irritant effects or both. On the other hand, slowly soluble particles depositing in the conducting airways are carried on the surface to the glottis and are swallowed within one day. Mucociliary transport rates are highly variable, both along the ciliated airways of a given individual and between individuals. The changes in clearance rates produced by drugs, cigarette smoke, and other environmental pollutants can greatly increase or decrease these rates. Particles deposited in non-ciliated airways have large surface-to-volume ratios, and clearance by dissolution can occur for materials generally considered insoluble. They may also be cleared as free particles either by passive transport along surface liquids or, after phagocytosis, by transport within alveolar macrophages. If the particles penetrate the epithelium, either bare or within macrophages, they may be sequestered within cells or enter the lymphatic circulation and be carried to pleural, hilar, and more distant lymph nodes. Non-toxic insoluble particles are cleared from the alveolar region in a series of temporal phases. The earliest, lasting several weeks, appears to include the clearance of phagocytosed particles via the bronchial tree. The terminal phases appear to be related to solubility at interstitial sites. While the mechanisms and dynamics of particle deposition and clearance are reasonably well established in broad outline, reliable quantitative data are lacking in many specific areas. More information is needed on: (1) normal behaviour, (2) the extent of the reserve capacity of the system to cope with occupational exposures, and (3) the role of compensatory changes in airway sizes and in secretory and transport rates in providing protection against occupational exposures, and in relation to the development and progression of dysfunction and disease.
PMCID: PMC1008751  PMID: 7004477
25.  Fever induced by fluorine-containing lubricant on stainless steel tubes. 
Three subjects, all smokers, handling stainless steel tubes suffered repeated attacks of general malaise, chills, and fever lasting for several hours, mainly after gas soldering. Provocations by rubbing smoking tobacco against a tube produced similar attacks, and leucocytosis, after a few hours. The presence of fluorine on the tubes and in the febrifacient tobacco was shown. A fluorocarbon polymer lubricant was suspected of causing the attacks. Heating (1000 degrees C) of the tubes eliminated the effect.
PMCID: PMC1008712  PMID: 7426482

Results 1-25 (67)