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1.  Thin-layer chromatography of hippuric and m-methylhippuric acid in urine after mixed exposure to toluene and xylene. 
The separation of hippuric and m-methylhippuric acid as toluene and m-xylene metabolites present in urine of people exposed simultaneously to toluene and xylene is described. Chloroform was used for hippuric and m-methylhippuric acid extraction. Satisfactory separation of these metabolites was obtained on TLC plates covered with silica gels and developed in chloroform acetic acid-water (4:1:1);p-dimethylaminobenzaldehyde in acetic acid anhydride was applied to develop the colour. The sensitivity of the method was 6 micrograms hippuric acid per 1 ml urine and recovery was 100% (+/- 1).
PMCID: PMC1008891  PMID: 7272246
2.  Prevalence of byssinosis in Swedish cotton mills. 
The prevalence of byssinosis and of chronic bronchitis was studied in a questionnaire investigation among workers in bale opening areas, carding rooms, and spinning rooms in five Swedish cotton mills. Airborne dust and Gram-negative bacteria was measured. Nineteen per cent of the interviewed workers reported symptoms of light byssinosis (grade 1/2). The prevalence of symptoms was not related to the duration of employment, and cases of byssinosis were found among people who had worked in cotton mills for only a few years. A significantly higher proportion of male than female workers reported symptoms. No difference in the extent of byssinosis was found between smokers and non-smokers, but the prevalence was significantly higher among those workers who had ceased smoking. The prevalence of byssinosis was related to the number of airborne viable Gram-negative bacteria as well as to the dust level in the different mills.
PMCID: PMC1008836  PMID: 7236538
3.  Cotton bacterial endotoxin assessed by electron microscopy. 
A piece of bale cotton was incubated in nutrient broth. Electron microscopic inspection of the cotton and the broth showed Gram-negative bacteria with long flagella, loosely attached to the cotton fibres. Large amounts of endotoxin liberating from these bacteria were visible in the growth medium.
PMCID: PMC1069296  PMID: 7032578
4.  Factors predisposing to the development of progressive massive fibrosis in coal miners. 
Altogether 238 759 miners employed by the National Coal Board were examined in the third of the Board's radiological surveys from 1969 to 1973 inclusive. Excluding those diagnosed as having progressive massive fibrosis (PMF) on that occasion, 210 847 were in collieries still operating at the time of the fourth survey four to five years later 132 728 attended for radiography at the same colliery on the second occasion, and were used to study the attack rate of PMF. In all groups in the age range 35-54 and having category 2 simple pneumoconiosis (SPN) or less, 80% or more had a second radiograph. It was found that the probability of developing PMF increased sharply with rising category of SPN; however, half the cases occurred in men having SPN categories 0 or 1, who were in the majority. Current coalface work had no significant effect on the attack rate. Age increased the attack rate of PMF within each major SPN category (0, 1, 2, and 3), especially the higher categories. All or part of this effect may have been due to the fact that SPN in younger men with categories 1 and 2 tends to lie in the lower range within these categories. Similarly, a lower distribution of SPN within each category associated with a low overall local prevalence may account wholly or in part for the great difference between the attack rates of PMF supervening on each category of SPN in Scotland and South Wales. The rank (quality) of coal mined had no effect on the attack rate.
PMCID: PMC1069281  PMID: 7317294
5.  First report of byssinosis in Hong Kong. 
There has been no report of byssinosis in Hong Kong although the textile industry has been one of the leading industries for many years. Three workers with a long history of exposure to cotton dust had chronic obstructive airways disease precipitated by their work environment. One had irreversible airways obstruction but none had chronic bronchitis, emphysema, or asthma. Only one gave a history of "Monday morning tightness," and this was attributed to the fact that most of the textile workers in Hong Kong work seven days a week. It was suggested that a survey be carried out to ascertain the importance of byssinosis in the textile workers of Hong Kong and tha byssinosis should there be added to the list of notifiable occupational diseases.
PMCID: PMC1008888  PMID: 7272243
6.  Erythrocyte factors concerned in the inhibition of ALA-D by lead. 
Erythrocyte factors are concerned in the inhibition of delta-aminolaevulinic acid dehydratase (ALA-D) by lead at 20 to 100 nM concentrations. The activity of the factors in detected in Hb fractions from Sephadex G-200 gel filtration of erythrocyte supernatant. After gel filtration of erythrocyte supernatant from a lead worker, 50% of lead is found in ALA-D fractions, although the fractions recover from ALA-D inhibition. The recovered activity is reinhibited if the enzyme fraction is preincubated with Hb fraction obtained from the same chromatography. Similarly obtained enzyme from a normal subject is also inhibited when it is preincubated with normal Hb fraction and lead acetate at 20 to 100 nM concentrations. The extent of the inhibition depends on the concentrations of Hb fraction and lead acetate preincubated. Reinhibition of lead worker enzyme with normal Hb fraction may be deleted not only by heating but also by zinc or DTT as well. Hb fraction heated at 60 degrees C for 5 min is also able to induce the lead-inhibition of the activity in ALA-D fraction. Half life of the factors is 26 min at 60 degrees C and 3 min at 80 degrees C.
PMCID: PMC1008885  PMID: 7272240
7.  Enhanced excretion of thioethers in urine of operators of chemical waste incinerators. 
Thioether concentrations were determined in urine samples obtained from ten workers in the despatch department (n = 69), three chemical waste incinerator operators (n = 67), and an analyst (n = 21), all working in the same chemical plant. Urine samples (n = 196) obtained from non-exposed men, including smokers, served as controls. Enhanced excretion of thioethers was found in urine samples taken from incinerator workers at the end of work. A regular pattern in the time course of the urinary thioether excretion was shown by a non-smoking incinerator worker; end-of-work values were always higher than prework values. This phenomenon was not found in samples obtained from the analyst. These findings suggest that incinerator workers inhale or otherwise absorb electrophilic compounds or their precursors, which are subsequently metabolised to, and excreted as, thioethers in urine.
PMCID: PMC1008845  PMID: 7195275
8.  Ventilatory function changes over a workshift. 
Thirty-four production workers at three chemical plants were tested for acute changes in lung function over the course of their three-day, twelve-hour workshift. Mean percentages of the predicted lung function indices (FVC, FEV, and FEF 25-75) showed a workshift decrement, particularly evident in the evening shift. A workweek effect was shown in that no recovery in mean %FEV1 and %FEF-25-75 was shown by the last working day. Diurnal variation in respiratory function was regarded as being only partly responsible for the observed workshift effect.
PMCID: PMC1008838  PMID: 7236540
9.  A study of the mortality of Cornish tin miners. 
Increased mortality from cancer of the lung has been found in several studies of miners exposed to high levels of radioactivity in underground air. In view of their exposure to raised levels of radiation, we have studied the mortality of a group of men recorded as Cornish tin miners in 1939. Using occupational description, a crude classification of exposure was derived for these miners. The meaningfulness of this classification was supported by differences in mortality from silicosis and silicotuberculosis. A twofold excess of cancer of the lung was found for underground miners, while for other categories mortality from this cause was less than expected. This supports the findings of previous studies on exposure to radon and its daughters. An excess of cancer of the stomach was also observed among underground miners.
PMCID: PMC1069292  PMID: 7317301
10.  Respiratory cancer in a cohort of nickel sinter plant workers. 
A study was undertaken of a cohort of nickel refinery workers from a sinter plant that operated from 1948 to 1962. A complete follow-up of the 495 workers has been carried out by searching death records and other measures. Incidence cases known to the Workmen's Compensation Board of Ontario have been included. Fifty-four cases of lung cancer and eight of sinus cancer (including two in men who subsequently developed primary lung cancer) were located. The risk of lung and sinus cancer was much higher in the earlier days of operation of the plant, with an increase rate of over 40% for those employed in the first year of operation. The dose-response relationship has been examined by regressions of standardised morality ratios (SMR) and standardised incidence ratios (SIR). The SIR suggests that the risk doubled at levels of exposure of 12 months (six months in the earlier years).
PMCID: PMC1069282  PMID: 7317295
13.  Arginase and kallikrein activities as biochemical indices of occupational exposure to lead. 
In a group of 60 workers occupationally exposed to lead the blood and urine lead concentrations, haematocrit, ALA-D and arginase activities, and urinary 5-aminolaevulinic acid (ALA) and coproporphyrin concentrations, and kallikrein activity were determined. Correlation coefficients of -0.78 and 0.77 for Pb-B/ALA and Pb-B/arginase were found respectively for lead concentrations above 40 microgram/dl blood, and 0.83, 0.76, 0.74, and -0.64 for Pb-U/ALA, Pb-U/Cp-U, Pb-U/kallikrein, and Pb.U/kallikrein, respectively. It seems that the increase in serum arginase activity may be indicative of liver damage while the decrease in kallikrein activity may indicate kidney damage in workers exposed to lead.
PMCID: PMC1008842  PMID: 6909029
14.  Relation between progressive massive fibrosis, emphysema, and pulmonary dysfunction in coalworkers' pneumoconiosis. 
The correlations between progressive massive fibrosis (PMF), emphysema, and impairment of ventilation were studied in 108 dead coalminers, all of whom had suffered with complicated coalworkers' pneumoconiosis (radiological category B or C) during life. The findings indicated that both factors were contributing to impairment of ventilation in proportion to their size or extent, but these contributions were in the main independent of one another. A joint opinion on the types of emphysema found to be present in a random 50 out of the 108 cases was given by two pulmonary pathologists. They found that most of the emphysema was of the centrilobular variety, which appeared to be unrelated to the PMF. The distribution of the PMF throughout the lungs both radiologically and anatomically is shown.
PMCID: PMC1008834  PMID: 7236536
15.  Experimental exposure to toluene: further consideration of cresol formation in man. 
In two separate experiments 10 healthy men each were exposed at rest in an exposure chamber to about 200 ppm toluene in the air. Hippuric acid, o-, m-, p-cresol, and phenol in urine were detected by capillary gas chromatography at the beginning and at the end of exposure, and at variable times after the cessation of exposure. In addition toluene in blood was determined at the same intervals. The results indicate that in addition to hippuric acid, o-, m-, p-cresol are metabolites of toluene; the detoxication lasting 24 hours at least.
PMCID: PMC1008847  PMID: 7236546
16.  Arsenic and selenium in lung, liver, and kidney tissue from dead smelter workers. 
Concentrations of arsenic and selenium in lung, liver, and kidney tissue from dead smelter workers and from a control group have been determined with the aid of neutron activation analysis. A sevenfold increase of arsenic was found in lung tissue from the exposed workers compared with the control group. The median value of arsenic in lung tissue from workers dead from respiratory cancer was not higher than corresponding values from workers dead from other malignancies or from cardiovascular or other diseases. With increasing period of retirement the malignancies or from cardiovascular or other diseases. With increasing period of retirement the arsenic content diminished in liver tissue but not in lung tissue, indicating a long biological half life of arsenic in lung tissue. The workers dead from malignancies had a higher As/Se quotient than workers dead from other diseases, which does not contradict the protective theory of selenium. Accumulation of antimony, cadmium, lead and lanthanum was observed in lung tissue from the exposed workers. Six of the workers died from lung cancer and the highest concentrations of any of the elements were always observed in the lung tissue from these six cases. This observation speaks in favour of a multifactorial cause behind the excess mortality from lung cancer in smelter workers.
PMCID: PMC1008843  PMID: 7236543
17.  Screening for occupational vitiligo in workers exposed to hydroquinone monomethyl ether and to paratertiary-amyl-phenol. 
Two men reported previously with vitiligo after occupational exposure to hydroquinone monomethyl ether (HMME) have been reviewed after eight years. Repigmentation of significant degree was found in one man and of limited degree in the other. One hundred and sixty-nine men in the same works have been screened with Wood's light for evidence of vitiligo. No cases were found in the 148 men exposed to HMME (colleagues who screened 100 men exposed to HMME in two other factories also found no case) or in the 129 who had been exposed to paratertiary-amyl-phenol. Loss of light reflection on Wood's light examination was observed in 13 men due to scars or to other skin disorders.
PMCID: PMC1069293  PMID: 7317302
18.  Magnitude and distribution of trunk stresses in telecommunications engineers. 
The incidence of back injuries has been shown to be greater in occupations as heavy manual work than light manual work. To plan a programme aimed at reducing the incidence of back injuries in industry those workers at high risk of incurring handling accidents and back injuries need to be identified and a knowledge of the specific occupational factors causing such injuries sought. This has been achieved for telecommunications engineers using epidemiological and radio pressure pill methodologies. The results verify the correlation between the back injury rates and physical work stresses of different occupational groups. The magnitude and relative frequency of trunk stresses in hazardous tasks has been determined and compared with those with lower incidences of back disorders. The study has confirmed that in examining manual handling hazards in industrial male populations a critical value of truncal stress can be applied and used to determine the safety of occupational factors in relation to their potential causing or contributing to degenerative back diseases.
PMCID: PMC1069290  PMID: 7317300
19.  Acute behavioral effects of styrene exposure: a further analysis. 
Studies were carried out on two groups to styrene-based resin. Early morning urinary mandelic acid concentrations after two days without exposure correlated with reaction time measured on arrival at work. Men were found to differ considerably in their rate of clearance of mandelic acid-those with slow reaction times. After some months at reduced exposure, a small group of men with previously high mandelic acid concentrations has speeded up on the reaction time task.
PMCID: PMC1069287  PMID: 7317297
20.  Hand-arm vibration in the aetiology of hearing loss in lumberjacks. 
A longitudinal study of hearing loss was conducted among a group of lumberjacks in the years 1972 and 1974--8. The number of subjects increased from 72 in 1972 to 203 in 1978. They were classified according to (1) a history of vibration-induced white finger (VWF), (2) age, (3) duration of exposure, an (4) duration of ear muff usage. The hearing level at 4000 Hz was used to indicate the noise-induced permanent threshold shift (NIPTS). The lumberjacks were exposed, at their present pace of work, to noise, Leq values 96-103 dB(A), and to the vibration of a chain saw (linear acceleration 30-70 ms-2). The chain saws of the early 1960s were more hazardous, with the average noise level of 111 dB(A) and a variation acceleration of 60-180 ms-2. When classified on the basis of age, the lumberjacks with VWF had about a 10 dB greater NIPTS than subjects without VWF. NIPTS increased with the duration of exposure to chain saw noise, but with equal noise exposure the NIPTS was about 10 dB greater in lumberjacks with VWF than without VWF. With the same duration of ear protection the lumberjacks with VWF consistently had about a 10 dB greater NIPTS than those without VWF. The differences in NIPTS were statistically significant. The possible reason for more advanced NIPTS in subjects with VWF is that vibration might operate in both of these disorders through a common mechanism--that is, producing a vasoconstriction in both cochlear and digital blood vessels as a result of sympathetic nervous system activity.
PMCID: PMC1008887  PMID: 7272242
21.  Behaviour of indicators of exposure and effect after cessation of occupational exposure to lead. 
The behaviour of blood lead (PbB) and of some indicators of effect (erythrocyte protoporphyrin IX (EP), delta-aminolaevulinic acid dehydratase activity of erythrocytes (ALAD), and urinary delta-aminolaevulinic acid (ALAU)) were studied in subjects who had ceased working with inorganic lead for at least one year. Relations between these indices and chelatable lead (PbU-EDTA (lead in urine after injection of CaNa2 EDTA 1 g intravenously)), a test that is used to evaluate the lead deposits in the body, were also analysed. As a comparison, a group of subjects currently exposed was studied. In the workers with past exposure the PbB values were significantly lower, at the same PbU-EDTA levels, than those found in subjects at work. The relation between EP and PbU-EDTA shows that, corresponding levels of chelatable lead, the values of the erythrocyte metabolite are identical in the two groups. Considering the EP-PbB relation, however, at the same PbB levels the protoporphyrin values appear distinctly more altered in the subjects with past exposure. Similar results were obtained from a study of the relations between ALAD and PbU-EDTA and between ALAD and PbB. The relation between ALAU and PbU-EDTA, however, shows that, at the same PbU-EDTA levels the urinary metabolic in past-exposed subjects is distinctly lower than in subjects at work, while the relation between ALAU and PbB shows that, for similar blood lead values, the ALAU levels are identical. On the basis of the results obtained it is concluded that in subjects with past exposure, EP and ALAD can be used in establishing the persistence and extent of an "active deposit" of lead in the organism, while PbB is of very limited use.
PMCID: PMC1008884  PMID: 7272239
22.  Nasal cancer in England and Wales: an occupational survey. 
A national survey of the incidence of nasal cancer in England and Wales during the period 1963-7 with special reference to occupation confirmed the well-known increases in incidence of nasal cancer in cabinet makers and wood machinists, together with the absence of any significant increase in carpenters and joiners, and the increases in boot and shoe operatives and repairers, and in nickel smelters in South Wales. The significant excesses of cases found among coalminers, furnacemen in the gas, coke, and chemical industry, and furnacemen and labourers in foundries may be associated with exposure to coal and coke dust or may be spurious. No excess of nasal cancer was found among male textile workers. Excesses of uncertain significance were found among tailors and dressmakers, bakers and pastry cooks, and printers. Apart from the well-known relationships between adenocarcinoma and work in the furniture and footwear industries there is no definite indication in this survey of any association between a particular histological type of nasal tumour and occupation in England and Wales.
PMCID: PMC1008878  PMID: 7272233
23.  Assessment of risk by biological monitoring. 
Variability between workers is reflected in differences in uptake, metabolism, and excretion of toxic substances, and thus individual response to toxic hazards. It is argued that biological monitoring takes account of these differences enabling individual risk assessments to be made. Risk, however, must be seen in terms of clinical and pathological changes-that is, estimated from morbidity and mortality rates-and so laboratory measurements need to be linked to epidemiological studies before they can be used to indicate acceptable or unacceptable uptake of toxic materials.
PMCID: PMC1008848  PMID: 7236547
24.  Correlation of urinary thioethers with chemical exposure in a rubber plant. 
Exposure to potentially alkylating in a rubber factory was measured by determining thioether concentrations in urine samples collected at the end of work on a Friday. The study population consisted of the total work force (113) in the production departments of a factory, and office clerks (111) in two factories of the same company. The highest excretion of thioethers was detected in female workers in the belt department who were exposed through the palmar skin. High excretion was also found in workers exposed to air-borne contaminants in the calender department and in workers in the raw material stores and chemical mixing sections. Lower values were found in this dispatching station and in the contaminant-free offices. Urinary thioether determination appears to be a reliable and easy method of assessing the exposure to certain rubber chemicals.
PMCID: PMC1008805  PMID: 7470409
25.  Locally induced digital vasospasm detected by delayed rewarming in Raynaud's phenomenon of occupational origin. 
The rewarming time of fingers after hand cooling to 10 degrees during ischaemia was significantly prolonged in all subjects with Raynaud's phenomenon of occupational origin compared with normal reaction and patients with primary Raynaud's phenomenon. The temperature is faster and easier to record than pressure or pulse volume. Population studies are in progress with the described technique.
PMCID: PMC1008803  PMID: 7470407

Results 1-25 (74)