Showing papers in "Occupational and Environmental Medicine in 1969"

Effects in man and rabbits of inhalation of cotton dust or extracts and purified endotoxins

Abstract: Cavagna, G., Foa V., and Vigliani, E. C. (1969). Brit. J. industr. Med., 26, 314-321. Effects in man and rabbits of inhalation of cotton dust or extracts and purified endotoxins. The incidence of byssinosis in workers in a cotton card-room, where the airborne concentration of bacterial endotoxins was 7·2 μg./m. 3 , was 32%; and 47% in a hemp card-room where the endotoxin concentration was 8·7 μg./m. 3 ; no cases were observed among workers exposed to only traces of endotoxins. The effect of the inhalation by aerosol of purified Escherichia coli endotoxin on F.E.V. 1·0 and F.V.C. was studied in normal subjects and in patients with chronic bronchitis. A significant reduction in F.E.V. 1·0 lasting more than 6 hours was observed in two out of eight normal subjects, in one out of three subjects with chronic bronchitis inhaling 80 μg. endotoxin, and in one out of four subjects with chronic bronchitis inhaling 40 μg. endotoxin. These results show that the inhalation of bacterial endotoxin can produce, in some individuals, changes in F.E.V. 1·0 similar to those experienced on Mondays by some card-room workers. A study of the mechanism of pathogenesis of inhaled bacterial endotoxins was carried out on rabbits subjected for 20 weeks to aerosols of purified E. coli endotoxin (20 μg./day) and cotton extract (2 mg./day). This treatment produced patterns of bronchitis: i.e., a increase in the respiratory tract fluid with increased protein content and characteristic histopathological changes. The bronchitis occurred after the appearance of cross-reacting circulating antibodies against E. coli endotoxin and cotton extract. These antibodies were detected with the haemagglutination tests after the first three weeks of treatment, and in subsequent weeks reached progressively higher titres, up to a maximum of 1:512. A challenging aerosol of 0·1 mg. E. coli endotoxin in two rabbits and 10 mg. cotton extract in another two of the rabbits treated as above produced a marked increase in pulmonary resistance lasting more than two hours. In control rabbits a challenging aerosol of 1 mg. endotoxin or 100 mg. cotton extract caused only a moderate increase in pulmonary resistance, which returned to normal in less than one hour. It may be concluded that the repeated inhalation of endotoxins induces in rabbits a state of hypersensitivity and at the same time the appearance of inflammatory reactions in the bronchi and alterations in the mechanical properties of the lung. These changes may be significant in the pathogenesis of byssinosis.

1967 Evaluations of Some Pesticide Residues in Food

Abstract: This volume has the limited objective of 'highlighting' new developments and findings in the field of industrial hygiene. It consists of a number of review articles which, unlike so many of the uncritical reviews of subjects in the scientific press, give reasoned, expert opinions on the current (1966/67) understandings of the subjects. Some chapters, particularly that on noise, give essentially American viewpoints which may not be wholly applicable to the British scene. Others, notably those dealing with analysis and toxicology, suffer from having subjects too broad for satisfactory review. Those on radiation, both ionizing and non-ionizing, hot environments, ergonomics, and air pollution are excellent. Industrial Hygiene Highlights will be a valuable addition to the library of those who wish to keep abreast of trans-atlantic thought, and should be bought as such, rather than as a textbook on the subject.

Theory and practice of colour vision testing: A review Part 1

Abstract: Lakowski, R. (1969).Brit. J. industr. Med.,26, 265-288. Theory and practice of colour vision testing: A review. Part 2. The more modern tests of colour confusion, hue discrimination, metamerism, and special aptitudes measure a wide variety of attributes. Norms, including variations among normal as well as among defective observers, are given for each test, along with any other information we require to understand them. Finally there is the problem of choice, and factors influencing it, of which tests should be used in different circumstances. Some advice is given on the most useful combinations of tests.

Health Factors Involved in Working under Conditions of Heat Stress

Abstract: 10-8 % in 1964-67. In some groups of collieries the fall in prevalence is quite marked, while in others the difference between the two periods is small or nil. The overall proportion of newly boarded cases of pneumoconiosis from the coal mining industry has dropped from 3 9 per thousand wage earners in 1962 to 1-8 per thousand in 1967. The rate of fall varies from division to division and is still at the highest level in the south-western division. Finally, it is pointed out that reorganization of the National Coal Board Divisions will necessitate constructing some of the tables on an area basis instead of a divisional basis. The Digest illustrates again the slow decline in prevalence of all forms of pneumoconiosis, more marked in the coal mining industry, with the exception of asbestosis which continues to rise. It is pointed out in the Digest that 'a rise in certification figures should not be taken as necessarily indicating that the prevalence of the disease is increasing'. Boardings at which asbestosis was first diagnosed have more than trebled in number since 1962, which could be due to both the recognition of longstanding cases and a true increase in prevalence. R. I. MCCALLUM

Significance of urinary hippuric acid determination as an index of toluene exposure.

Abstract: Ikeda, Masayuki, and Ohtsuji, Hatsue (1969).Brit. J. industr. Med.,26, 244-246. Significance of urinary hippuric acid determination as an index of toluene exposure. Urine samples from 118 male workers in photogravure printing factories were analysed for hippuric acid. The urinary levels of hippuric acid were proportional to the environmental concentrations of toluene, although within wide variations. The urinary concentration of hippuric acid corresponding to 200 p.p.m. of toluene was 3·5 g./litre (specific gravity 1·016) or 4·3 g./g. creatinine.

Quantitative determination in urine of hippuric acid and m- or p-methylhippuric acid, metabolites of toluene and m- or p-xylene

Abstract: Ogata, M., Tomokuni, K., and Takatsuka, Y. (1969).Brit. J. industr. Med.,26, 330-334. Quantitative determination in urine of hippuric acid and m- or p-methylhippuric acid, metabolites of toluene and m- or p-xylene. Improved and more specific methods for the quantitative determination of hippuric and m- and p-methylhippuric acids in urine are described. The acids were extracted from urine with ether/ethanol, which was dried with silica gel, or with ethyl acetate. After removing the solvent by evaporation coloured azlactones were formed by reaction with p-dimethylaminobenzaldehyde in acetic anhydride (DAB, only usable after ether/ethanol extraction) or benzenesulphonyl chloride in pyridine, and the absorbances were measured. The sensitivities were about 4 μg./ml. of urine using DAB, and 20 μg./ml. of urine using benzenesulphonyl chloride reagent. Separation of hippuric and methylhippuric acids was achieved by paper and thin-layer chromatography before estimation. A spot test is also described.

An investigation of lead absorption in an electric accumulator factory with the use of personal samplers.

Abstract: Williams, M. K., King, E., and Walford, Joan (1969).Brit. J. industr. Med.,26, 202-216. An investigation of lead absorption in an electric accumulator factory with the use of personal samplers. Thirty-nine lead workers and controls, in stable conditions of exposure, each wore personal lead-in-air samplers daily for two weeks. During the second week samples for blood lead, urinary lead, urinary coproporphyrin, urinary δ-aminolevulinic acid (ALA), the punctate basophil count, and haemoglobin were taken daily. Duplicate estimations were made on one day. The lead exposures of men doing almost identical jobs differed by ratios of up to four to one. This could be attributed only to personal differences in working habits. The correlation coefficients and regression equations of the biochemical tests with lead-in-air and with each other were determined. The mean values and 95% confidence limits of single determinations of some of the biochemical tests corresponding to the two commonly accepted TLVs of lead-in-air (0·20 and 0·15 mg./m.3) were calculated from the regression equations. For each biochemical test the variation due to analytical error, the variation from day to day within subjects and the residual variation due to analytical error, and the residual variation about the regression on lead-in-air were calculated. Previous estimates of the latter are not known. Excessive confidence may be placed in an index of exposure due to its low coefficient of variation within subjects unless the coefficient of variation between subjects about regression is taken into account. This correction for specific gravity of estimations of lead and ALA in spot samples of urine was found to reduce slightly the residual variation between subjects about the regression on lead-in-air and to increase the correlations with lead-in-air and with the other biochemical tests, but these changes were not statistically significant. The modified method used for estimating blood lead and urinary lead is described and validated.

A study of the mortality of workers in an asbestos factory.

Abstract: Newhouse, M. L. (1969).Brit. J. industr. Med.,26, 294-301. A study of the mortality of workers in an asbestos factory. A cohort study of over 4,500 male workers employed at an asbestos factory making both textiles and insulation materials is described. The main analysis of the mortality of workers employed between April 1, 1933, the date of the implementation of the Asbestos Regulations, and May 1, 1964. The analysis was made in relation to job, length of exposure, and length of follow-up after first exposure. There was no significant difference between the number of deaths occurring in the factory population and the national figures, until an interval of 16 years or longer had elapsed from first exposure in the factory. There were 1,160 men who fulfilled this criterion. In this group there was no excess mortality among those who worked in jobs where exposure was low or moderate, but among those with jobs which entailed heavy exposure there was a significant excess of deaths from cancer of the lung and pleura, and cancer of other sites, in men with a total period of employment in the factory of less than two years, as well as with those who worked for longer. Excess mortality from respiratory disease was observed only among severely exposed workers with long service.

Circadian variation of F.E.V. in shift workers

Abstract: Guberan, E., Williams, M. K., Walford, Joan, and Smith, Margaret M. (1969). Brit. J. industr. Med., 26, 121-125. Circadian variation of F.E.V. in shift workers. The one-second forced expiratory volume (F.E.V. 1·0 ), the forced vital capacity, and the oral temperature were measured in a group of men working a rotating three-shift system—2 to 10 p.m. one week, 10 p.m. to 6 a.m. the next week, and 6 a.m. to 2 p.m. the third week. The outside air temperature at the London Weather Centre was also obtained. Measurements were made on Mondays and Fridays at the beginning, middle, and end of the shift. The mean F.E.V. 1·0 of 19 normal men showed an increase of 0·15 litre (4·1%) between the beginning and end of both the morning shifts, a mean decrease of some 0·05 litre (1·5%) between the beginning and end of the afternoon shifts, and little change during the night shifts. This circadian variation could not be attributed to industrial fume, smoking or a learning effect. The findings will be of practical importance when F.E.V. is measured in shift workers to determine the effects of toxic substances on ventilatory capacity.

A simple method for the quantitative analysis of urinary delta-aminol evulinic acid to evaluate lead absorption

Abstract: Wada, O., Toyokawa, K., Urata, G., Yano, Y., and Nakao, K. (1969).Brit. J. industr. Med.,26, 240-243. A simple method for the quantitative analysis of urinary delta-aminolevulinic acid to evaluate lead absorption. A procedure is given for the rapid, quantitative determination of urinary delta-aminolevulinic acid (ALA). Interfering substances are removed by n-butanol extraction. After pyrrole formation with ethyl acetoacetate, Ehrlich9s reagent is added to produce the chromophore, which is then extracted with chloroform and measured spectrophotometrically or by comparison of the depth of colour with standard colour solutions. The recoveries were about 91% and the results agreed well with those obtained using ion-exchange column chromatography (r=0·985). This assay is simple, dependable, and suitable for large-scale screening of industrial workers exposed to lead poisoning, because the critical level of urinary ALA (20 mg./l. urine), which indicates dangerous lead absorption, gives a convenient absorbance.

A rapid method for estimating mercury in undigested biological samples.

Abstract: Magos, L., and Cernik, A. A. (1969). Brit. J. industr. Med., 26, 144-149. A rapid method for estimating mercury in undigested biological samples. A method has been developed for estimating mercury in biological samples using an ultraviolet mercury detector, after liberating the mercury from the urine and other biological samples by a simple chemical method. The overall time for one estimation is less than two minutes, and no special skills are required to operate the technique. The principle of the method is that stannous chloride at high p H liberates mercury from sulphhydryl bonds and converts the liberated mercury into volatile metallic mercury which is subsequently estimated by an ultraviolet photometer. Stannous chloride is added to the acidified sample, and the presence of extra cysteine ensures that no appreciable amount of mercury is lost before the reaction is triggered by the addition of excess sodium hydroxide. The standard solution of mercury developed is stable for months and behaves in the reaction like urine, and, because of its stability, the instrument can be standardized with it frequently and conveniently.

Exposure of spray operators to paraquat

Abstract: Swan, A. A. B. (1969).Brit. J. industr. Med.,26, 322-329. Exposure of spray operators to paraquat. Two field-trials in Malaysian rubber plantations are described in which operators applied paraquat for weed control with hand-operated knapsack sprayers. The extent of systemic absorption was assessed by weekly estimation of urinary paraquat concentrations during and after a 12-week period of continuous spraying. Periodic medical examinations, including chest radiographs, were made before and during the trials and for some weeks afterwards. The conditions of continuous operation with paraquat were probably close to the extremes of exposure likely to occur in any agricultural operation, but the investigations have shown that ordinary care in personal hygiene is sufficient to prevent any hazard from surface injury or from systemic absorption.

Epidemiology of Chronic Non-specific Lung Disease (Chronic Bronchitis)

Abstract: 10-8 % in 1964-67. In some groups of collieries the fall in prevalence is quite marked, while in others the difference between the two periods is small or nil. The overall proportion of newly boarded cases of pneumoconiosis from the coal mining industry has dropped from 3 9 per thousand wage earners in 1962 to 1-8 per thousand in 1967. The rate of fall varies from division to division and is still at the highest level in the south-western division. Finally, it is pointed out that reorganization of the National Coal Board Divisions will necessitate constructing some of the tables on an area basis instead of a divisional basis. The Digest illustrates again the slow decline in prevalence of all forms of pneumoconiosis, more marked in the coal mining industry, with the exception of asbestosis which continues to rise. It is pointed out in the Digest that 'a rise in certification figures should not be taken as necessarily indicating that the prevalence of the disease is increasing'. Boardings at which asbestosis was first diagnosed have more than trebled in number since 1962, which could be due to both the recognition of longstanding cases and a true increase in prevalence. R. I. MCCALLUM

Intracellular distribution of lead in the liver and kidney of the rat

Abstract: Castellino, N., and Aloj, S. (1969).Brit. J. industr. Med.,26, 139-143. Intracellular distribution of lead in the liver and kidney of the rat. The distribution of lead in intracellular fractions of liver and kidney has been studied in rats for nine days after intravenous injection of 100 μg. of lead (210Pb) per rat. The radioactivity and the protein nitrogen have been measured in the homogenates and in the nuclei, mitochondria, microsomes, and cell sap. Lead penetrates the cells quickly, being present in all fractions one hour after injection. During the first 72 hours the relative amounts of lead in the different fractions varied, which ruled out the possibility that all the differences could be explained by redistribution after homogenization. The distribution of the metal within the cell probably depends upon differences in the nature and the stability of bonding to intracellular structures. The binding of lead within the mitochondria seemed to be particularly stable, only 24·4% of the radioactivity being removed by washing with 0·25 m sucrose or 0·001 m ethylenediaminetetra-acetate or 0·001 m diethylenetriaminopenta-acetate in 0·25 m sucrose. This finding is discussed in relation to haem biosynthesis within the mitochondrion.

Validation of death certificates in asbestos workers

Abstract: Newhouse, M. L., and Wagner, J. C. (1969). Brit. J. industr. Med., 26, 302-307. Validation of death certificates in asbestos workers. The Registrar General has supplied the certified cause of death of 436 past workers in an asbestos factory. An attempt was made to follow up the 301 (69%) deaths which had occurred in hospital or had been the subject of an inquest or coroner9s post-mortem examination. Necropsy reports were obtained for 158 (52%) of this group and histological material was reviewed in 84 (28%). The additional information, particularly that obtained from review of the histology, led to the revision and extension of the diagnosis suggested by the certified cause of death in a number of cases. The incidence of carcinoma of the bronchus had not been grossly underestimated, four additional tumours of this type were identified by scrutiny of the necropsy reports, and a further four by review of histological sections. The incidence of mesothelial tumours was underestimated, endothelioma or mesothelioma was the certified cause of death in four of the series, and a further 15 mesotheliomata were identified by review of histological material. Five patients with pleural mesotheliomata had been certified as dying of carcinoma of the lung or pleura. Ten deaths from peritoneal mesotheliomata had been attributed either to carcinomatosis without mention of a primary tumour or to cancer of the gastro-intestinal tract. Lung sections were submitted for review in 67 of the series; some degree of asbestosis was found in all but seven. Asbestosis graded as either moderate or severe was found in all the confirmed cases of carcinoma of the lung.

Sleep and wakefulness in a group of shift workers

Abstract: Tune, G. S. (1969).Brit. J. industr. Med.,26, 54-58. Sleep and wakefulness in a group of shift workers. Fifty-two shift workers recorded their hours of sleep and wakefulness for a period of 10 weeks. Compared with matched non-shift-working control subjects it was found that they took a higher average duration of sleep per 24 hours and more and longer naps outside the major sleep period. A comparison of the on and off duty records from the shift workers showed that a sleep debt was incurred during the former which was largely paid off by taking long naps in the latter. It is suggested that the longer sleep taken by shift workers may be necessary in order to pay off specific kinds of sleep debt.

Hippuric acid, phenol, and trichloroacetic acid levels in the urine of Japanese subjects with no known exposure to organic solvents

Abstract: Ikeda, M., and Ohtsuji, H. (1969).Brit. J. industr. Med.,26, 162-164. Hippuric acid, phenol, and trichloroacetic acid levels in the urine of Japanese subjects with no known exposure to organic solvents. Urine samples from 36 male and 30 female university students and 31 male factory workers with no known exposure to industrial organic solvents were analysed for hippuric acid, phenol, and trichloroacetic acid, which are the major metabolites of toluene, benzene, and trichloroethylene respectively. The normal levels were less than 1·4 g./l. for hippuric acid, less than 80 mg./l. for phenol, and less than 1 mg./l. for trichloroacetic acid. No evidence was obtained to suggest that correction for urine concentration with either specific gravity or creatinine concentration minimizes individual variation of metabolite levels.

The mortality and morbidity of deep sea fishermen sailing from Grimsby in one year.

Abstract: Moore, S. R. W. (1969).Brit. J. industr. Med.,26, 25-46. The mortality and morbidity of deep sea fishermen sailing from Grimsby in one year. The injuries, illnesses, and deaths of Grimsby deep sea fishermen in the year 1963 have been studied using the trawler log-book as the basic source of information. Additional information has been obtained from other sources. The numbers of man-days sailed by Grimsby deep sea fishermen, by age and rating in 1963, have been ascertained. From these, incapacity rates for the measurement of morbidity due to injury and illness, and the mortality rate, have been calculated. There were 14 deaths, six due to accidental causes and eight to natural causes, giving a mortality rate of 5·7 per 1,000 for Grimsby deep sea fishermen in 1963. In a year when there was no foundering or loss of Grimsby trawlers, the fatal accident rate of Grimsby trawlermen was more than twice that of fishermen of the United Kingdom, four times the rate for miners, and 40 times that for the manufacturing industries. The most common injuries were, in order of incidence, contusions of varying degrees of severity, infected lesions, sprains and strains, lacerations, and fractures. More than half (56·3%) of the trawlermen were incapacitated by their injuries. The highest rates of incapacity were caused by fractures, contusions, and infected lesions. The upper limb, especially the hands and fingers, was most often affected, resulting most commonly in infected lesions. Third hands, mates, deck hands, deck trimmers, and deck learners had the highest incapacity rates due to injury. Third hands are especially at risk to injury. Most injuries and two deaths caused by casualties to boats occurred in fires aboard trawlers. The most common illnesses suffered by trawlermen were gastrointestinal, respiratory, and skin diseases. Illness caused incapacity in 68·8% of the trawlermen affected. The greatest incapacity was due to gastrointestinal, cardiac, psychiatric, and respiratory illness, and firemen, third-hands, and cooks had the highest rates of incapacity. Of the illnesses said to be peculiar to fishermen, Dogger Bank itch and erysipeloid did not affect Grimsby trawlermen. Unfit deep sea fishermen go to sea, even when so certified by a medical officer, thus possibly endangering themselves and other members of the crew. The injuries which give rise to the highest morbidity and mortality in deep sea fishermen are primarily due to accidental causes. The following measures are suggested to reduce the toll on deep sea fishermen. (1) The establishment of an occupational health service for trawlermen, with compulsory pre-employment and periodic examinations, would help to prevent unfit men going to sea and ensure that those sailing were of good health and not a liability to their fellows. The Medical Examination (Fishermen) Convention, 1959, of the International Labour Organization should be ratified by the United Kingdom.

Effects of carbon disulphide on the liver of rats

Abstract: Bond, E. J., Butler, W. H., de Matteis, F., and Barnes, J. M. (1968).Brit. J. industr. Med.,26, 335-337. Effects of carbon disulphide on the liver of rats. Normal rats surviving a single oral dose of carbon disulphide (CS2) show liver enlargement and depression of drug-metabolizing enzymes but no liver necrosis. If the drug-metabolizing enzymes are stimulated by phenobarbitone before exposure to CS2, the LD50 does not change but liver necrosis is produced.

Hygiene Standards for Chrysotile Asbestos Dust.

Abstract: Dr. T. A. Lloyd Davies is to be congratulated on both setting up this advisory panel and producing this memorandum. His panel is well chosen, representing academic and practical experts with a keen interest in this particular problem, so that it is not surprising that the report is an excellent summary of the present position in the British asbestos industry. The report does not underestimate the problem that has been created by the rapid expansion in volume and variety of asbestos usage just at a time when the dangers of late development of malignancy have been recognized. It emphasizes the unsatisfactory conditions which still exist in some parts of the industry. The recognized deaths from asbestosis are still rising-18 per year on the average for 1951-60 whereas 64 died in 1966 and of these 30% and 66%, respectively, died of lung cancer or mesothelioma. It also points out that there may be similar unsatisfactory working conditions in other trades using asbestos which have not been recognized. In formulating their recommendations the panel discuss both the evidence from industry concerning the effect of safety measures and the epidemiological evidence relating mesotheliomas to crocidolite exposure. They point out that whereas satisfactory safety standards can now be laid down for the factory use of chrysotile, standards for the factory use of other forms of asbestos, especially crocidolite, can only be guessed at. Similarly, the use of asbestos and asbestos-containing materials in other industries is as yet uncharted territory apart from the insulation workers. With respect both to standards of safety and to crocidolite and mesotheliomas the panel point out the need for further research before precise recommendations can be made. The panel strongly recommend that all asbestosexposed workers, whether they are in trades already known to be hazardous or not, should have a preemployment examination and regular periodic examintions. They require this for the early detection of evidence of pulmonary fibrosis in the hope that exposure levels sufficient to cause asbestosis or cancer of the lung canbe stopped as soon as possible. They doubt the value of periodic examination for the prevention of mesothelioma and are unwilling to specify the stage at which an asbestos worker should be withdrawn from further exposure. It is against the background of this memorandum and the equally good Hygiene Standards for Chrysotile Asbestos Dust issued by the British Occupational Hygiene Society that the current 'Draft Regulations' should be viewed and found wanting.

Respiratory effects of chlorine gas.

Abstract: Beach, F. X. M., Sherwood Jones, E., and Scarrow, G. D. (1969).Brit. J. industr. Med.,26, 231-236. Respiratory effects of chlorine gas. Seven chemical workers who were accidentally exposed to chlorine gas in separate accidents were investigated. The usual symptoms were cough, dyspnoea, and chest pains, the symptoms starting within 10 minutes of exposure and lasting two to eight days. Chest radiographs showed congestion, consolidation, and nodules; lung oedema was also present in a severe case. These changes usually cleared within one week but in the severe case persisted for 10 weeks. Three patients had respiratory failure. Hypoxaemia was found in four patients and was quickly corrected by oxygen therapy in three of them, but in the severe case hypoxaemia persisted for four days despite continuous oxygen therapy. All the patients recovered completely.

Ventilatory function in workers exposed to low levels of toluene diisocyanate: a six-month follow-up.

Abstract: Peters, John M., Murphy, Raymond L. H., and Ferris, Benjamin, G., Jr. (1969).Brit. J. industr. Med.,26, 115-120. Ventilatory function in workers exposed to low levels of toluene diisocyanate: a six-month follow-up. Thirty-four workers exposed to toluene diisocyanate during production of polyurethane foam were examined with a respiratory questionnaire and tests of ventilatory capacity. The tests of pulmonary function were conducted on Monday morning and afternoon and on Tuesday morning and afternoon. Twenty-eight of these 34 workers had been examined with the same tests six months earlier. On Monday a mean change in the one-second forced expiratory volume (F.E.V.1·0) of –0·16 l. occurred that did not return to the baseline value (Monday a.m.) on Tuesday morning. A statistically significant decrease in all the measurements of ventilatory capacity except the forced vital capacity occurred over the six months in the 28 workers. The F.E.V.1·0 fell an average of 0·14 l. and flow rates at 75%, 50%, 25%, and 10% of vital capacity also decreased significantly. There was a highly significant correlation coefficient (r = 0·72) between one-day changes in F.E.V.1·0 (measured six months earlier) and six-month changes in F.E.V.1·0. Workers with respiratory symptoms (cough and/or phlegm) demonstrated greater falls in F.E.V.1·0 than did asymptomatic workers. All air concentrations of toluene diisocyanate measured during this study were below the threshold limit value (0·02 p.p.m.).

Absence from work and physical fitness

Abstract: Linden, V. (1969).Brit. J. industr. Med.,26, 47-53. Absence from work and physical fitness. The distribution of sickness absence in a given population is not one of chance but is governed by the nature of the individuals making up the group. Earlier studies strongly suggested that an individual factor was operating. The present paper is concerned with the possible influence of a physical factor. Are those who repeatedly absent themselves from work less physically fit than those who do not, and are the former, in carrying out their work, overtaxing their respiratory and circulatory systems? Pilot studies were carried out on 203 employees from different occupations. Physical fitness was determined by measurement of the maximal oxygen uptake during performance of dynamic work. A bicycle ergometer of the mechanical braking type was used. For 51 customs officers, an inverse relationship between maximal oxygen uptake and number of absences from work was found. No such relationship was found for 56 firemen, which might have been expected because they form a selective group. So far as male and female office workers were concerned, no relationship was found between the maximal oxygen uptake and number of absences. Some morphological recordings were also made. No relationship was found between the data for height, weight or skinfold thickness and the maximal oxygen uptake or number of absences. Continuous, telemetric heart rate recording, which roughly indicates the level of oxygen uptake, was performed in 10 employees from different occupations during whole working days. Five were `repeaters9, i.e., persons with many sickness absences for different and unrelated conditions, occupied with non-sedentary work. They were found to have much higher heart rate recordings than some of their fellow-workers used as controls. The former thus made higher demands on their vital systems than the latter, and they were physically overtaxed by their daily work. No investigation was made in this study with regard to the extent these men may be trained physically. Three were postmen who had been following that occupation for more than 20 years; they did not seem to benefit from the physical training apparently involved in their work. Repeaters having subnormal physical fitness will probably never be able to cope with strenuous physical work. Preventive measures such as physical training programmes should be taken early in their lives. Vocational guidance at the start of their working careers is also necessary.

An elaboration of the I.L.O. classification of simple pneumoconiosis.

Abstract: Liddell, F. D. K., and Lindars, D. C. (1969). Brit. J. industr. Med., 26, 89-100. An elaboration of the I.L.O. classification of simple pneumoconiosis. Simple pneumoconiosis in chest radiographs presents a continuum of increasing abnormality. Liddell (1963) introduced a 12-point scale obtained by dividing each of the four I.L.O. categories (International Labour Office, 1959) into one central and two marginal zones. In this system, which has come to be known as the N.C.B. elaboration, readers record for each radiograph the I.L.O. category of choice (0, 1, 2 or 3), followed by an adjacent I.L.O. category if that had been seriously considered; otherwise, the same category is repeated. Very clear normals are denoted as 0/-, and `high9 category 3 films as 3/4. This paper reviews the evidence from seven reading trials in which 12 National Coal Board (N.C.B.) film readers have taken part. About 28,000 assessments on a total of well over 2,000 single radiographs have been analysed. (The reading of serial radiographs to assess progression is dealt with elsewhere.) All readers used the elaboration successfully, but they differed in the extents to which they placed films in central and in marginal zones; they were more consistent when preliminary briefing had been given. Film quality had little influence on the use of the zones, except that 0/- tended to be reserved for films of good quality. Despite the variation in the use of the zones, marked improvements accrued from the use of the elaboration in both intra- and inter-observer error for all readers, and for films of poor quality as well as for good films. The validity of expressing simple pneumoconiosis prevalence rates in terms of I.L.O. categories derived from N.C.B. elaboration readings was confirmed. Although the exact widths of the zones along the continuum remain to be determined, all the evidence suggests that they represent steadily increasing abnormality. Thus, the N.C.B. elaboration is a practical procedure which amplifies, but neither distorts nor supplants, the I.L.O. classification. It is reported to be easier to use.

An investigation of allergy in byssinosis: sensitization to cotton, hemp, flax and jute antigens

Abstract: Popa, V., Gavrilescu, N., Preda, N., Teculescu, D., Plecias, M., and Cirstea, M. (1969).Brit. J. industr. Med.,26, 101-108. An investigation of allergy in byssinosis: sensitization to cotton, hemp, flax, and jute antigens. The authors investigated allergy to cotton, hemp, flax, and jute in 41 subjects with byssinosis. In contrast with immediate skin reactions, which were seldom observed, delayed reactions were nearly always present. The incidence of positive skin tests in byssinosis was similar to that observed in all textile workers. Inhalation tests with textile allergens were negative in all but four subjects who also had a concomitant bronchial asthma. Fifteen out of 31 subjects with byssinosis had positive inhalation tests to acetylcholine but only one of the 13 tested had a positive response to the inhalation of textile macerate. Haemagglutinating antibodies to low titres could be observed in byssinosis as well as in chronic bronchitis, in bronchial asthma, and in the general population. The significance of various types of antibodies existing in byssinosis is further discussed. The authors stress the need to standardize textile allergens.