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4.  Premalignant and neoplastic skin lesions associated with occupational exposure to “tarry” byproducts during manufacture of 4,4'-bipyridyl 
ABSTRACT Skin lesions have been identified in 20 workers manufacturing 4,4'-bipyridyl. The lesions were on the face, neck, and backs of the hands and arms. Larger localised lesions were removed surgically and examined histopathologically, but other lesions have been treated topically with fluorouracil cream. Histological diagnosis showed a progression from keratosis to Bowen's disease and, in six cases, to squamous cell carcinoma. Over 550 individuals associated with 4,4'-bipyridyl processes between 1961 and 1980 have been examined or questioned. All 20 patients identified worked in now obsolete production plants; 15 of whom were found among the 147 shift process operators. The time taken for the lesions to appear from first working on a 4,4'-bipyridyl plant was 6-19 years (average 12 years). Starting in the early 1960s three processes have been successively used to convert pyridine into 4,4'-bipyridyl. These differ in the reaction conditions used and in the efficiency of the conversion. In the two earlier plants a substantial quantity of pyridine was converted into polypyridyls and “tarry” byproducts, which caused operating difficulties and increased the risk of worker exposure. The exposure and occupational histories of the cases, including the fact that two had worked only on the obsolete production plants, indicates that the causative agent was present in these earlier processes. In-vitro tests for potential carcinogenicity on materials from the present plant and from an earlier process gave positive tests on the tarry byproducts from the earlier process, suggesting that they were the cause of the lesions. Tar impurity production on the present plant is minimal, and worker exposure to chemicals is low. No similar skin lesions have been seen in those who have worked only on the present plant. This observation supports the view that the causative agent was present only on the earlier plants but is not conclusive because of the shorter time that has elapsed since first exposure of personnel who have worked only on the present plant. Medical surveillance of past and present 4,4'-bipyridyl workers is continuing.
PMCID: PMC1008931  PMID: 7066224
5.  Phosphorus Necrosis of the Jaw: A Present-day Study 
A historical note on the aetiology of phossy jaw shows that present-day knowledge is little greater than it was a century ago. The varied clinical course of the disease is described together with a report of 10 classical cases not previously reported. Six cases, not amounting to true necrosis but in which healing after dental extraction was delayed, and described, and mention is made of the noticeable differences in the oral state and appearances of tartar of healthy workmen exposed to phosphorus compared with healthy workmen not exposed. But no systematic differences of any kind were found in the incidence of general infections, fractures of bones, haematological findings, and biochemical studies of blood and urine in two groups of healthy men most exposed and least exposed to phosphorous in the same factory. An intensive study in hospital of a case of classical necrosis showed no departure from normal, except delayed healing following bone biopsy from the iliac crest, and a reversed polymorphonuclear/lymphocyte ratio.
In the discussion the time of onset of necrosis after first exposure to phosphorus, clinical and radiological diagnosis, the organisms present, personal susceptibility, the appearance of the sequestra, and regeneration of bone are considered. An up-to-date note on prevention of the disease is given, although this has met with only partial success. Some persons are highly susceptible and, whilst complete protection is impossible in the light of our present knowledge, early diagnosis and modern treatment have robbed the disease of its terrible manifestations of Victorian times and turned it into a minor, although often uncomfortable complaint, with little or no resulting disability.
PMCID: PMC1038164  PMID: 14449812
6.  A Study of the Reproducibility of the Forced Vital Capacity of Coalworkers at Two Collieries in Scotland and Two Collieries in South Wales 
A study of 1,522 coalworkers at two Scottish collieries and two Welsh collieries showed that the forced vital capacity (F.V.C.) was as reproducible a measurement as the forced expiratory volume (F.E.V.) (1 sec.). This applied not only to replicate readings, but also between readings taken before and after a working shift on the same day, and also between readings taken at an interval of one week. An examination of the results of F.E.V. (1 sec.) and F.V.C. readings taken on the entire colliery populations at a colliery in Ayrshire, Scotland, and one in South Wales showed that replicate readings of F.V.C. and F.E.V. (1 sec.) were equally reproducible and that reproducibility was virtually unaffected by the presence or absence of bronchitic symptoms or the different prevalence of pneumoconiosis at the two collieries.
PMCID: PMC1038035  PMID: 13818464

Results 1-6 (6)