Chronic bronchitis in Victoria, New South Wales and Queensland

A study of chronic bronchitis was carried out on 195 ex-servicemen from Victoria New South Wales and Queensland. Exacerbations of chest symptoms were commonly found and chronic bronchitis was in important cause of haemoptysis. Weather conditions, especially cold weather, affected chest symptoms and early age of starting to smoke affected the incidence of severe bronchitis. The clinical profiles of the cases studied were similar to those in some of the reports from Canada and Britain.

Salmefamol and Salbutamol in exercise-induced asthma in children

A double-blind controlled study is reported of salmefamol 200 mug and salbutamol 200 mug administered by aerosol before exercise tests in asthmatic children. Both drugs prevented exercise-induced asthma. There was no significant difference between them.

Clinical comparison of two electronic spirometers with a water-sealed spirometer

Two electronic spirometers which use a hot-wire anemometer to measure air flow were clinically compared with a water-sealed spirometer. The forced vital capacity (FVC), the forced expiratory volume in one second (FEV1), the FEV1/FVC%, the mean forced expiratory flow between 200 and 1,200 ml of the FVC, the mean forced expiratory flow during the middle half of the FVC, the mean forced expiratory flow between 75 and 85 percent of the FVC, and the maximum voluntary ventilation were determined for a group of 67 subjects. Techniques are described for connecting the spirometers in series to permit evaluation by human subjects or by syringe injection. High correlation coefficients generally were obtained when comparing the electronic spirometers with the water-sealed spirometer, but the actual range of percent difference was greater than 11 percent in all spirometric tests. The results indicate the need for systematic evaluation of electronic spirometers to characterize their deviation from accented standards. Frequent calibration is necessary to maintain consistent performance.

The effect of thymoxamine and cromolyn sodium on postexercise bronchoconstriction in asthma

Of the 22 patients with extrinsic bronchial asthma, 13 patients developed post-exercise bronchoconstriction after treadmill exercise, whereas in 9 patients treadmill exercise had no effect on the ventilatory capacity. No statistical difference in the resting lung volumes and CO transfer factor was found between the two groups. A significant inhibition of postexercise bronchoconstriction was observed in 12 of 13 patients following thymoxamine or cromolyn sodium inhalation. Inhibition of postexercise bronchoconstriction by alpha blockade with thymoxamine suggests that increased alpha adrenergic activity in the presence of diminished beta receptor responsiveness to catecholamines, norepinephrine released during exercise could have a marked alpha agonistic effect giving rise to bronchoconstriction. It has been suggested that cromolyn sodium has a cyclic phosphodiesterase inhibiting action. This might increase levels of AMP and restore the beta receptor responsiveness to catecholamines.

Development of "resistance" in beta-adrenergic receptors of asthmatic patients

Complete in vitro dose-response curves for (see article) -isoproterenol (isoprenaline) sulfate showed no functional defects in bronchial muscular beta-adrenergic receptors in three patients with chronic intrinsic asthma, as compared to 60 patients with normal pulmonary function. Complete in vivo dose-response curves for intravenously infused isoproterenol were obtained in eight outpatients with chronic intrinsic asthma to register effects on bronchial muscle (forced expiratory volume in one second), heart rate, blood pressure, and skeletal muscular tremor. The isoproterenol test was performed before and also during oral treatment with a long-acting selective beta-adrenergic stimulator (terbutaline sulfate, 5 mg three times daily). The study was performed over 12 months to avoid seasonal variation in basal levels of obstruction and was concluded by adding inhaled terbutaline (two inhalations four times daily) to oral therapy. No "resistance" developed in bronchial beta-adrenergic receptors during this prolonged treatment. Inhalation therapy in addition to oral therapy improved bronchodilation without causing resistance. Even six inhalations given four times daily (four- to five-hour intervals) did not cause any bronchial resistance; however, resistance developed in skeletal muscles with decreased tremor and in cardiac beta-adrenergic receptors.

Comparison of the bronchodilating effects of SCH 1000 with isoproterenol in patients with bronchial asthma

The effect of SCH 1000 and isoproterenol was evaluated in 10 patients with extrinsic asthma. The onset of action for the SCH 1000 dose compared to the baseline response occurred at or before 15 minutes (FEV1 and MEFR). The onset of action for the isoproterenol dose occurred at or before one minute for all three pulmonary function variables. At the 1-, 3-, 6- and 15-minute intervals the response to the isoproterenol dose was significantly greater than the response to the SCH 1000 dose for FEV1, FVC and MEFR. At 30 and 60 minutes, however, the response to SCH 1000 was progressively increasing, whereas the response to isoproterenol was decreasing. The maximum improvement in FEV1 for isoproterenol was 49% at three and six minutes, whereas for SCH 1000 was 28% at 60 minutes. In patients with chronic bronchitis or bronchial asthma SCH 1000 may be considered as a therapeutic alternative to beta-adrenergic bronchodilators and in patients who also have cardiac arrythmias or angina pectoris and are adversely affected by sympathomimetic drugs.

Chronic nonspecific respiratory disease in Berlin, New Hampshire, 1967 to 1973. A further follow-up study

The 1967 sample of Berlin, New Hampshire was resurveyed in 1973 by means of a standard questionnaire on respiratory symptoms and by simple tests of pulmonary function. Measurements of the levels of air pollution showed a decrease in the number of suspended particulates and an increase in the concentration of sulfation. These values were close to the Federal Primary Standard. No differences in respiratory symptoms, prevalences of chronic, nonspecific respiratory disease, or pulmonary function were detected. Within the limitations of this study, we concluded that the Federal Primary Standards for sulfur dioxide and total suspended particulates are probably adequate to protect the public.

A short-term double-blind trial of aerosol triamcinolone acetonide in steroid-dependent patients with severe asthma

Twenty-five steroid-dependent severely asthmatic patients, ranging in age from 20 to 67 years, were hospitalized. Baseline laboratory and pulmonary function testing was followed by reduction of prednisone therapy to 5 mg daily and by entry into a randomized double-blind study of placebo vs active aerosol triamcinolone acetonide (300mug four times daily). In this four-week trial, aerosol triamcinolone acetonide further reversed airway obstruction and proved to be an effective substitute for large oral doses of steroids in steroid-dependent patients with severe asthma. No significant improvement occurred in the maximum midexpiratory flow or the maximum velocity of air flow after 50 percent or 75 percent of the vital capacity had been expelled. There was no significant difference in the frequency of untoward effects between the groups taking aerosol triamcinolone acetonide and its vehicle. No patient demonstrated any definite return of adrenal function.

Asthma: comparative bronchodilator effects of ipratropium bromide and isoproterenol

The effect of ipratropium bromide administered at two dosage levels, 40 and 80 mug, isoproterenol, 150 mug, and placebo using a metered dose inhaler was evaluated in ten adult patients with asthma in a double-blind, crossover study. The new atropine-like drug proved to be as effective a bronchodilator as isoproterenol in this study, although it had a later peak effect. Ipratropium bromide had a longer course of action than isoproterenol (4 hours compared to 1-2 hours) and was free of significant side effects. The larger dose of the new drug produced a slightly greater and longer-acting effect than the smaller dose. Ipratropium bromide seems to have had bronchodilator effects on both large and small airways.

Determination of the optimum dose of subcutaneous salbutamol in asthmatic patients

Saline and salbutamol (250 mug, 500 mug, 750 mug, and 1000 mug) injections were administered under double-blind conditions to seven chronic stable asthmatic patients. The response on the respiratory system (FEV1, FVC) and cardiovascular system (pulse rate, blood pressure and ECG) was monitored for 3 hours. Increasing the dose of salbutamol increased the peak and weighted average effects of FEV1 and pulse rate. The optimum dose, a titration of desired increases in FEV1 and undesirable increases in pulse rate, is 500 mug but doses up to 1000 mug may be administered if necessary.

Normal values for ventilatory function in Rhodesian Africans

Forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow were measured in 141 African men and 102 African women aged 20 and above. Prediction formulae relating each measurement to height and age were drawn up and are presented. Rhodesian Africans have lower values for these measurements than subjects in some Europen and North American series, but broadly similar values to those of Africans elsewhere.

Respiratory responses to CO2-rebreathing in Nigerian men

In 36 young Nigerian men, ventilatory capacity and the changes in ventilation, tidal volume and tidal P CO2 during oxic CO2-rebreathing have been measured. CO2 response lines and breathing rhythms have been determined and analysed in relation to the anthropometric and lung function data. Previous findings that Nigerian men have a substantially lower ventilatory capacity than Europeans at a standard height and age are confirmed. Breathing rhythms in Nigerians appear to be the same as in other ethnic groups studied. CO2-sensitivity varies with FVC, as found previously in Europeans and New Guineans. However, at a standard FVC of 41, Nigerian men have the same CO2-sensitivity as Europeans, and not a lower value like New Guineans.

The effect of beta adrenergic blockade on bronchial sensitivity to acetyl-beta-methacholine in normal and allergic rhinitis subjects

The effect of propranolol inhalation on sensitivity to methacholine inhalation was studied in normal and allergic rhinitis subjects to determine whether beta adrenergic blockade alters sensitivity to mediators in nonasthmatic atopic individuals. A partial beta adrenergic blockade is suggested as being instrumental in asthma. Hay fever patients studied showed similar effects and also developed asthma for the first time.

Lung function in asymptomatic cigarette smokers--the single breath nitrogen test

The modified single breath nitrogen (SBN) test and simple spirometry were used to study the lung function (LF) of 101 asymptomatic, cigarette smoking and 20 non-smoking men aged 18 to 39 years. Abnormal LF was demonstrated in 39% of smokers. An abnormal SBN test was found in 28% of the light and 56% of the heavy smokers but only 3% were spirometrically abnormal. Only one non-smoker had an abnormal SBN test. Closing volume and slope of the alveolar plateau, which are both measured from the SBN test, correlated poorly suggesting that the abnormality caused by smoking may differ among smokers. The SBN test is a simple test which is sensitive enough to detect LF abnormalities in young smokers. The significance of the detected abnormalities in relation to the development of chronic obstructive lung disease is not presently known.

Transfer factor for the lung, airway obstruction and hyperinflation in chronic bronchitis and emphysema

The interrelationships of breath holding lung transfer factor (TCO) and transfer coefficient (KCO) with ventilatory obstruction (FEV1.0) and FEV1.0/VC) and hyperinflation (RV and RV/TLC) were studied in 37 patients with chronic nonspecific lung disease with a FEV1.0 of 1.5 litre or less classified as "bronchitic", "emphysematous" or "intermediate" according to Nash, Briscoe and Cournand (1965). No relationships could be found between TCO and airway obstruction or hyperinflation. KCO tended to decrease as RV increased (r=-0.26) and was weakly related to the FEV1.0/VC ratio in "intermediate" (r=0.34) and "emphysema" (r=0.29) patients but these relationships were nonsignificant.

Chronic respiratory disease in hemp workers. A follow-up study, 1967-1974

Many soft-hemp workers with more than 20 years' exposure to dust have chronic respiratory symptoms and obstructive lung function loss. During 7 years of follow-up, these workers had significantly higher occurrences of chronic cough and phlegm and dyspnea than control subjects and a significantly larger annual decline of forced expiratory volume in 1 second (FEV1.0) than control subjects, with a particularly marked difference between 20- to 44-year-old nonsmoking controls and hemp workers. We believe that deterioration of lung function among hemp workers begins before the age of 45 and that it continues even if further exposure to dust ceases. Textile workers should be advised to avoid further exposure to dust at a time when their ventilatory lung function (in the absence of effects of acute exposure) is sufficient to prevent future development of disabling function loss.

The diagnosis of aspirin idiosyncrasy by analgesic challenge

Analgesic challenge was employed to identify fifty patients with aspirin idiosyncrasy. No serious reactions were observed using the method described. Patients with a history of the condition were highly sensitive and reacted to small doses of aspirin or to paracetamol. Patients with a positive challenge test, but previously unaware of aspirin idiosyncrasy, were less sensitive: they required larger challenge doses of aspirin and did not respond to paracetamol challenge. In the absence of an in vitro test, analgesic challenge is the only means of confirming the presence of aspirin idiosyncrasy.

Effects of beta-adrenergic blockade and stimulation on airways in normal subjects

The effects of propranolol and salbutamol on conventional pulmonary function tests and closing volume have been studied in ten normal subjects. Propranolol and salbutamol had minor effects on measurements of airways resistance but had no effect on closing volume which is particularly sensitive to changes in peripheral airways. It was concluded that propranolol had negligible overall effect on central and peripheral airways properties in normal subjects, and it would appear that β-adrenergic activity has little measurable influence on peripheral airways in normal man at rest.

Comparison of an electronic spirometer with a pediatric Wright Peak Flow Meter and their relationship to clinical symptomatology in asthmatic children

To evaluate the correlations between the Wright Peak Flow Meter and an Electronic Spirometer with clinical symptomatology in chronic asthmatic chidlren, objective measurements of Peak Flow (PF) on both electronic (Vanguard Electric Spirometer) and mechanical (Wright Peak Flow Meter) Spirometers, Forced Vital Capacity (FVC), Forced, Expiratory Volune 1/2 second (FEV 0.5), Forced Expiratory Volume 1/2 per cent (FEV 0.5%), AND Maximal Midexpiratory Flow Rate (MMEFR) were obtained. Subjective observations of clinical wheezing were recorded immediately before each flow rate by trained nurses. PF determinations of both the mechanical and electronic spirometers were in close agreement. PF on the electronic spirometer correlated best with clinical wheezing in this study. The MMEFR calculated from the electronically produced graphys had the nex best coefficient of corelation. These were followed by the PF measured mechanically on the WPFM.

Ventilatory defects in atypical mycobacteriosis. A comparison study with tuberculosis

Two hundred thirty-two patients infected with Mycobacterium kansasii and 120 patients infected with M. intracellulare who were admitted to the East Texas Chest Hospital between 1965 and 1974 were individually matched according to age (+/- 5 years), sex, and extent of disease with an equal number of patients infected with M. tuberculosis. The ventilatory function in these patients was compared. The frequency of obstructive ventilatory defect, defined as forced expiratory volume in 1 sec less than 70 per cent of forced vital capacity, was greater among M. kansasii patients (68.9 per cent of 232) than among M. tuberculosis patients less than 80 per cent of predicted, was greater among M. intracellulare patients (68.3 per cent of 120) than among M. tuberculosis patients (57.5 per cent of 120). Above age 40, obstructive ventilatory defects tended to be more common in M. kansasii patients, whereas restricted ventilatory defects tended to be more common in M. intracellulare patients when compared with the same age group of M. tuberculosis patients. As expected, ventilatory function values among the M. tuberculosis groups decreased as extent of disease increased. In contrast, among the M. kansasii and M. intracellulare groups, these values were poorly related to the extent of disease; values were relatively low even with minimal extent of disease. It is suggested that the increased ventilatory defects among the M. kansasii and M. intracellulare patients could be accounted for by coexistent lung disease.

[Peripheral airway obstruction in the course of occupational exposure to asbestos]

Typically, the functional abnormalities in individuals exposed to asbestos dust take the form of a pulmonary fibrosis. Recently, several authors have stressed the early existence of small airways obstruction. In the present study, by measurement of closing volume, we have confirmed an obstructive factor in a certain number of exposed subjects, even if they were non-smokers, i.e. had no other apparent reason for small airways disease.

Effects of swimming training on children with asthma

In a programme to examine the effect of 5 months of swimming training on school-children with asthma, 46 children swam a total distance of 3608 km (2242 miles) during 2806 training sessions. On post-training re-examination, nonspecific effects of physical conditioning were detected including improved posture and fitness, reduced fat folds, and enhanced swimming ability. Continuous monitoring of asthma and medication showed significant decreases in both parameters during the final phases of the study between children who continued to swim regularly and those who did not. The frequency and severity of exercise-induced asthma (after running) was unchanged by swimming training. Post-training questionnaires indicated a high degree of enthusiasm and acceptance of the programme by children and parents. No significant adverse effects were observed or reported during the study.

Asthma due to inhaled chemical agents--amprolium hydrochloride

A man with no previous history of allergy or chest disease developed asthma after exposure to a heavy atmospheric concentration of amprolium hydrochloride which is a constituent of a poultry-food additive. Subsequent experimental exposure produced an immediate asthmatic reaction which was inhibited by sodium cromoglycate.

Relationship of constitutional factors and cigarette smoking to decrease in 1-second forced expiratory volume

A 5-year prospective survey of 34 subjects with mild chronic bronchitis revealed marked individual variation in the annual rate of decrease in the forced expiratory volume in 1 sec. The mean annual decrease in the 1-sec forced expiratory volume was 0.046 +/- 0.057 liter. Although the annual decrease in the 1-sec forced expiratory volume was greater among smokers (0.056 +/- 0.061 liter per year) than non- and ex-smokers (0.016 +/- 0.021 liter per year; P less than 0.005), differences in tobacco consumption did not account for the individual variation. This variation was related, instead, to 3 phenomena believed to indicate the presence of host susceptibility to chronic bronchitis. These phenomena were bronchial reactivity to methacholine, ventilatory responsiveness to isoproterenol, and sputum eosinophilia. The correlation between the rate of decrease in 1-sec forced expiratory volume and the degree of methacholine reactivity was 0.76 (P less than 0.001); the correlation between the decrease in 1-sec forced expiratory volume and ventilatory responsoveness to isoproterenol was 0.45 (P less than 0.01). Deterioration of 1-sec forced expiratory volume was appreciably greater among those with sputum eosinophilia (0.062 +/- 0.06 liter per year) than among thse without eosinophilia (0.017 +/- 0.033 liter per year P less than 0.01). The progression of abnormality appeared to depend on an interaction between cigarette smoking and individual susceptibility. Even minimal tobacco consumption led to serious ventilatory deterioration when methacholine reactivity was high, whereas heavy smoking produced little effect on the decrease in 1-sec forced expiratory volume when methacholine reactivity was slight.

A study of a new bronchodilator: carbuterol

A new oral bronchodilator, carbuterol, was studied in 9 subjects who had reversible airway obstruction. In addition to the spirometric changes, serial arterial blood gas determinations were done to see if the drug induced hypoxemia. Two- and 4-mg doses were compared with the placebo. There was a significant bronchodilating effect with the 4-mg dose beginning 30 min after administration of the drug. Maximal improvement of forced expiratory volume in 1 sec was observed at 4 hours, with a 42 per cent increase from the baseline. No significant hypoxemia was observed. The drug was considered an effective bronchodilating agent, with the effect lasting longer than 4 hours.

Extrinsic allergic alveolitis in Scottish maltworkers

In a survey of respiratory disease in the Scottish malting industry 5.2% of employees were found to have symptoms of extrinsic allergic alveolitis. In most cases the disease was mild and not associated with any serious respiratory disability. It was significantly less common where modern mechanical methods of malting were used. Mycological and serological studies suggested that it was usually caused by a type 3 allergic reaction to Aspergillus clavatus.

Sodium cromoglycate in chronic asthma

A long-term double-blind trial of sodium cromoglycate (SCG) with and without isoprenaline, with a placebo control, was undertaken in Edinburgh to a similar design as a previously reported trial in London. The results from the two centres were compared and combined. In Edinburgh 41 patients were studied for 36 weeks and 40 for 52 weeks and in the combined series 121 were studied for 36 weeks and 114 for 52 weeks. In the second year 14 patients were followed-up in Edinburgh and 27 in London. The two SCG regimens were superior overall to placebo both in the Edinburgh and London patients. SCG was effective in similar proportions of patients with extrinsic and intrinsic asthma. In the second year the effectiveness of SCG was further tested by randomly allocating half the patients to a placebo. Some patients derived a continuing benefit from SCG, but its continued use did not appear to be necessary for others, whose progress on placebo was satisfactory.

Salmefamol orally in asthmatics - two doses compared

The responses of twelve patients with chronic asthma to salmefamol 1 mg and 2 mg, taken orally, were compared in a double-blind cross-over study. Both produced a rise of 40-50% in PEFR and FEV1. Statistically significant improvements were maintained for three to four hours, and 20% improvements for four to six hours. There was no significantly different effect on ventilatory capacity between the two doses. After the 2 mg dose there was a statistically significant fall in diastolic blood pressure at 1 and 1 1/2 hours. Four patients experienced tremor and this was the only side-effect noted. The possible reasons for failure to demonstrate a greater effect with the higher dose are discussed.

Effects of oxprenolol on the airways of normal and bronchitic subjects

In a double blind trial in 11 control subjects and 12 bronchitic patients against an inert control oxprenolol produced significant worsening in airways obstruction in 6 control and in 7 patients. There was marked individual variation in response and no way was found to predict the susceptible subjects. Objective measurement of indices of airways obstruction and the effects of oxprenolol on them is essential where there is significant respiratory impairment. Great care must continue to be exercised since a significant proportion of bronchitic patients will be adversely affected by this drug.

Comparison of salmefamol with salbutamol aerosols in asthamatics

In twelve asthmatic patients 200 mug of salmefamol and salbutamol given by metered aerosol produced a similar initial effect on FEV1, FVC and PEFR without significant effect on heart rate or blood pressure. The duration of effect of salbutamol was approximately 4 hours; there was still an appreciable effect from salmefamol at 8 hours.

Pulmonary function evaluation during the Skylab and Apollo-Soyuz missions

Previous experience during Apollo postflight exercise testing indicated no major changes in pulmonary function. Pulmonary function has been studied in detail following exposure to hypoxic and hyperoxic normal gravity environments, but no previous study has reported on men exposed to an environment that was both normoxic at 258 torr total pressure and at null gravity as encountered in Skylab. Forced vital capacity (FVC) was measured during the preflight and postflight periods of the Skylab 2 mission. Inflight measurements of vital capacity (VC) were obtained during the last 2 weeks of the second manned mission (Skylab 3). More detailed pulmonary function screening was accomplished during the Skylab 4 mission. The primary measurements made during Skylab 4 testing included residual volume determination (RV), closing volume (CV), VC, FVC and its derivatives. In addition, VC was measured in flight at regular intervals during the Skylab 4 mission. Vital capacity was decreased slightly (-10%) in flight in all Skylab 4 crewmen. No major preflight-to-postflight changes were observed. The Apollo-Soyuz Test Project (ASTP) crewmen were studied using equipment and procedures similar to those employed during Skylab 4. Postflight evaluation of the ASTP crewmen was complicated by their inadvertent exposure to nitrogen tetroxide gas fumes upon reentry.

Spirometric values for normal Perth children aged six to twelve years

The purpose of this study was to construct tables and nomograms of spirometric norms for Perth children aged between six and 12 years. These norms were to be based on anthropometric measurements and age. A sample of 623 children was tested of which 556 were analysed and comprised 289 boys and 267 girls. All testing was carried out in the child's own school. The spirograms were recorded with a dry spirometer from which the FVC, FEV1, and FMF were measured. Correlation coefficients were established between each of these ventilatory parameters and anthropometric measurements of height, mass, arm span and age. The findings of the study revealed high correlations for both boys and girls between ventilatory parameters of FVC and FEV1 and height, mass, arm span and age. Moderately high correlations were found for both sexes between FMF and height, mass, arm span and age. Height correlated best with each of these ventilatory measures. It was also established that significant improvement in some correlations was obtained when anthropometric values were used in multiple correlation analysis. The use of height plus mass proved to be best when predicting FVC and FEV, for boys and girls, and for predicting FMF of girls. FMF for boys could be best predicted by using height alone. The limits of normality for ventilatory parameters of FVC, FEV1 and FMF were found to be best defined by the per cent standard error of the estimate. Tables and nomograms were established from regression and multiple regression equations in order to predict normal values in children. The findings of this study revealed that little difference existed between the ventilatory values of children tested in Perth, Europe and the Eastern States of Australia. However, the differences that were found to exist could be due to the age group which was sampled or possible environmental and genetic differences.

Chronic bronchitis--measurements and observations over 10 years

A total of 111 patients with chronic bronchitis were selected for study in 1963. By 1974 only 54 patients were available for clinical examination, chest radiography, and pulmonary function measurements. There was a significantly higher mortality compared with men of the same age and in the same locality, and this was due to cardiorespiratory failure and bronchial carcinoma. Reduction of cigarette smoking, declining atmospheric pollution, and antibiotic treatment have reduced the 24-hour sputum volume of these patients. The initial one-second forced expiratory volume (FEV1) and vital capacity were significantly lower in those patients who later died from cardio-respiratory failure. The duration of antibiotic treatment and the smoking record have not significantly affected the decline of the FEV1 with advancing age. The transfer factor (diffusing capacity) for carbon monoxide (TF) has declined more in those who continued to smoke. Of the 54 patients 14 had radiological evidence of emphysema initially. This has shown little change over 10 years.

Baritosis: a benign pneumoconiosis

Baritosis is one of the benign pneumoconioses in which inhaled particulate matter lies in the lungs for years without producing symptoms, abnormal physical signs, incapacity for work, interference with lung function, or liability to develop pulmonary or bronchial infections or other thoracic disease. Owing to the high radio-opacity of barium, the discrete shadows in the chest radiograph are extremely dense. Even in the most well-marked cases with extreme profusion of the opacities, massive shadows do not occur. When exposure to barium dust ceases the opacities begin slowly to disappear. Nine cases of baritosis occurring in a small factory in which barytes was crushed, graded, and milled are described. Two of the cases occurred after only 18 and 21 month's exposure, and 9 of the 10 men employed for more than one and a half years had baritosis. Five of the affected men examined at intervals since their exposure to barytes ceased in 1964 showed marked clearing of their radiological abnormalities.

Follow-up of ventilatory lung function in a group of cement workers

In a group of 160 active cement workers and 80 control workers selected on the basis of having or not having symptoms of chronic bronchitis, forced vital capacity (FVC) and one second expiratory volume (FEV 1-0), both corrected for age and height, and ratio of one second forced expiratory volume to forced vital capacity (FEV 1-0/FVC (%)) were measured on two occasions with an interval of four and eight years respectively.

Subacute effects of heavy marihuana smoking on pulmonary function in healthy men

To evaluate the subacute effects of heavy marihuana smoking on the lung, pulmonary function was tested in 28 healthy young male experienced cannabis users, before and after 47 to 59 days of daily ad-libitum marihuana smoking (mean of 5.2 marihuana cigarettes per day per subject, 2.2 per cent delta9-tetrahydrocannabinol). Base-line pulmonary-function studies were nearly all within normal limits, but after 47 to 59 days of heavy smoking, statistically significant decreases in forced expired volume in one second (3 +/- 1 per cent, S.E.), maximal mid-expiratory flow rate (11 +/- 2 per cent), plethysmographic specific airway conductance (16 +/- 2 per cent) and diffusing capacity (8 +/- 2 per cent) were noted as compared with the base-line studies. The decreases in maximal mid-expiratory flow rate and specific airway conductance were correlated with the quantity of marihuana smoked. These findings suggest that customary social use of marihuana may not result in detectable functional respiratory impairment in healthy young men, whereas very heavy marihuana smoking for six to eight weeks causes mild but statistically significant airway obstruction.

Prevalence of pneumoconiosis and chronic bronchitis in foundry workers

The prevalence of pneumoconiosis, chronic bronchitis, and impaired lung function was studied among those 1,000 foundry workers (response rate 93.1%) with the longest exposure time (minimum 4.2, mean 17, SD 9 years) from a representative sample of 20 foundries. Pneumoconiosis was diagnosed from 100 x 100 mm radiographs, and the false positives and false negatives were evaluated from normal-size radiographs from all those with a positive finding and a sample of those with a negative finding. Chronic bronchitis was studied by means of a translation of the MRC Short Questionnarie on Respiratory Symptoms. Forced vital capacity and forced expiratory volume in 1 s were measured with a Vitalograph Single Breath Wedge Spirometer, and the FEV % was calculated from these variables. The subjects were grouped according to smoking habits and dust exposure, which could be fairly well evaluated from measurements performed in connection with the health survey. All comparisons were made between different subcategories. The overall prevalence of pneumoconiosis was 3.8%, when allowance had been made for false positive and false negative findings. Most cases were mild. Chronic bronchitis occurred more frequently among those occupied in jobs classified as dusty. Smoking also strongly increased its prevalence; a combination of both exposures produced the strongest effect. The effect of smoking was also evident as an impairment of lung function; however, no such effect of dust exposure could be shown in this material. Since this was a prevalence study, the selective removal of workers from dusty jobs probably led to underestimates of all the health effects studied. In spite of the effect of selection excess bronchitis could be demonstrated in workers from dusty environments. Therefore effective dust control must be initiated not only with regard to silica dust but also with respect to total dust.

Elevated plasma antidiuretic hormone levels in status asthmaticus

Elevated plasma antidiuretic hormone (ADH) levels were noted in seven patients with status asthmaticus during the acute illness. These values returned to normal with resolution of the disease. The mechanism of this release is not completely understood but is consistent with the hypothesis that bronchospasm leads to decreased pulmonary blood flow, decreased volume return to the left atrium, and stimulation of the atrial volume receptors regulating ADH release. Planning for fluid therapy in patients with status asthmaticus should take into account a high probability of increased plasma ADH concentration during the acute illness. Water intoxication as well as hypoxia and hypercarbia should be considered as a possible cause of an altered state of consciousness associated with status asthmaticus.

Respiratory morbidity in rubber workers: II. Pulmonary function in curing workers

Pulmonary function tests were conducted on 121 curing and 189 control workers in 1972; 87% of the 1972 cohort was resurveyed one year later. The curing workers were subdivided into high and low exposure groups on the basis of environmental sampling. Cross-sectionally, in the 1972 cohort, the residual forced vital capacity was significantly decreased (P greater than .01) among the the heavily exposed workers (266 ml). Longitudinally, the mean one-year loss of forced expiratory volume in one second (FEV1.0) (173 ml/yr) in the curing workers with more than ten years of exposure was significantly greater (P less than .01) than in the control groups. Pulmonary function tests before and after a day's work were conducted on 29 curing-room workers. The eight heavily exposed curing workers had a significant decrease (P less than .05) in FEV1.0 of 115 ml. Our findings are sufficient to conclude that heavy exposure to curing fume affects pulmonary function. We recommend reduction of exposure and further longitudinal studies, especially in regard to those most heavily exposed.

Comparison of respiratory and cardiovascular effects of isoproterenol, propranolol, and practolol in asthmatic and normal subjects

Pulmonary functions, by means of FEV1, FVC, and airway resistance, and cardiovascular responses, i.e., ECG, blood pressure, and pulse contour, were measured in 10 control and 15 symptom-free asthmatic subjects during and after the infusions of isoproterenol, with or without previous administration of propranolol or practolol. Bronchial sensitivity to methacholine and response to isoproterenol after methacholine were also measured. Bronchial sensitivity to methacholine challenge was markedly enhanced by propranolol and the effect of isoproterenol infusion on the pulmonary function was also significantly diminished, whereas practolol did not reveal any effect on bronchial sensitivity to methacholine or isoproterenol. The above changes were much more profound in symptom-free asthmatic subjects than in control subjects. The results suggest that practolol does not significantly affect the beta-2 bronchial receptors, is safe to use in asthmatic subjects, and is consistent with an abnormality of these receptors in bronchial asthma.

Use of beta-adrenoreceptor blockers in combination with beta-stimulators in patients with obstructive lung disease

Lung function can be reduced not only by a non-selective beta-blocker but also by a selective beta1-receptor blocker. If both types of drug are without intrinsic sympathomimetic activity, the effect of the non-selective drug is more pronounced than that of a beta1-receptor selective drug under basal conditions. The effect of a beta2-receptor stimulating drug on the bronchi is inhibited by a non-selective drug, but much less by a selective beta1-receptor blocker. A selective beta1-receptor blocker can be used in asthmatics when it is combined with optimal anti-asthmatic therapy, while a non-selective drug is contra-indicated in patients with broncho-obstructive diseases. It is necessary to induce bronchodilatation (e.g. with a beta2-stimulator) in order to test whether or not a beta-blocker can be used in broncho-obstructive disease.

Medical implications of marijuana use

The effect of marijuana smoking was studied in 28 healthy young adult men who had previously smoked marijuana for approximately 5 years each. The subjects were hospitalized on a closed research ward for 31 days during which comprehensive psychological, physiological, and medical observations and tests were done. Physical examinations, neurological examinations, chest X-rays, electrocardiograms, and clinical laboratory tests were all within normal limits. Marijuana produced inconstant changes in pulse rate and blood pressure in these studies. Six subjects were found to have significant reduction in resting vital capacity during the baseline period of the study which were felt to be related to their prior marijuana smoking. In contradistinction to these findings, 12 of 15 subjects had statistically significant increases in peak expiratory flow rate immediately following marijuana smoking. Body temperature tended to be slightly reduced during marijuana use.

Intermittent assisted ventilation. An assessment using the Retec breathing assistor

A simple ventilator assistor was utilised in three of six patients after transthoracic repair of hiatus hernia. The device was found to be easy and convenient to use but in the pilot study produced no demonstrable improvement in respiratory function. At 10 days postoperation, the arterial oxygen tension had not risen to a preoperative level in five patients, and the FVC and FEVI were less than the values obtained before surgery in every patient.

Occupational type test for the etiological diagnosis of asthma due to toluene di-isocyanate

An occupational type exposure-test to toluene di-isocyanate (TDI) for the diagnosis of specific respiratory sensitization is proposed. The subjects were tested by exposure to a two-pot polyurethane varnish with and without TDI activator, using a paint-spraying system under standard and controlled conditions, so as not to exceed the threshold limit value of TDI. Forced expiratory volume per second and specific airway resistance (plethysmographic method) were measured before each exposure and during the following 24 h. 47 subjects with clinical symptoms of asthma were examined during their hospital care. For the purpose of this study they were divided into two groups: 42 workers exposed to TDI and 5 not exposed. The preliminary control test, using polyurethane varnish without TDI activator, was always negative and no significant changes in ventilatory parameters were recorded. The spray-painting test, with the same varnish and TDI activator, gave positive responses in 35 out of the 42 exposed workers and negative findings in the group not exposed. This method permits to formulate an accurate diagnosis of TDI respiratory sensitization in the majority of cases (83%). Immediate asthmatic reactions were frequently observed in the exposed subjects with high acetylcholine reactivity. Ten subjects showed a late bronchial reaction (3 h or more after TDI exposure).