Comparison of measured and predicted ventilatory volumes in selected groups of industrial workers.

A follow-up study of ventilatory volumes [forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0) and maximum expiratory flow at 50% of the FVC (MEF50)] was conducted for selected groups of workers from two plants involving the electrolytic extraction of aluminum (two groups with 95 and 38 workers, respectively), a cement industry (50 workers with chronic bronchitis and 96 healthy workers)and a shipyard (38 workers) during a period of 3 or 4 a. In the workers from the aluminum plant, particularly in those who were older and exposed longer to respiratory irritants, the fall in FVC was much higher than expected. Cement workers also showed a tendency towards more decreased FVC values than expected, and the fall in MEF50 was particularly pronounced. The cement workers with chronic bronchitis had a slightly higher annual fall in the ventilatory volumes than the healthy cement workers. The observed fall in the MEF50 of the shipyard workers without a specific occupational exposure to dusts or respiratory irritants was unexpectedly high. An analysis of the relative values of the ventilatory volumes within the groups indicated individual differences among the exposed workers in regard to a possible chronic effect of occupational exposure to respiratory irritants. A drop in the ventilatory volumes during the follow-up period was not found to be directly dependent on the initial volume values. In the evaluation of the results, selection factors and ambient exposure to irritants were taken into account.

The difference in complex psychomotor reaction time between patients with and without signs of cerebral circulatory disorders.

On a sample of 65 subjects rheoencephalography (REG)--the electrical impedance plethysmographic method for assessment of cerebral circulation was applied, as well as an electronic psychodiagnostic instrument Complex Reactionmeter Drenovac (CRD) constructed for assessment of complex psychomotor reactions. The aim of this study was to evaluate the potential differences between subjects with and without signs of cerebral circulatory disorders with regard to speed, stability and accuracy of complex psychomotor reaction. The results revealed that variable "maximal speed" on CRD showed significant difference between the groups, in favor of the control group.

Work environment and health in VDT use. An ergonomic approach.

Work-related health complaints were analysed in 90 operators of visual display terminals (VDT) and in 130 control office workers in regard to their assessment of environmental factors and work organization. The most common work-environment-related complaints concerned dry or stuffy or smoky air, poor ventilation, passive smoking and high temperature (14-71%). Fatigue (78%), headache (53%) and eye disturbances (48%) were more pronounced in VDT operators than in the other workers. Among the complaints relating to work organization the most important were lack of autonomy for both groups (26-34%) and the pressure to be productive for VDT operators. Physical factors accounted for 11.5-41% of the variation in the work-related health problems; VDT use accounted for only 1.9-7.5%. The high rate of work-related complaints and health symptoms seemed to be related more to personal, environmental and organizational characteristics than to VDT use.

Respiratory health of children at schools near a fertilizer plant.

In an investigation carried out over a six-month period in 1990 and 1991 the effect of exposure to possible air pollutants from a fertilizer plant on the respiratory health of preadolescent children was estimated. Data about children and their home environment were collected from physical measurements at school and from a questionnaire which was administered to the parents. Simultaneously, air pollution measurements were undertaken. The school children were placed into two groups according to the distance of the school from the plant. The incidence of acute respiratory disorders was 24%. The mean values of forced expiratory volume (FEV1) were slightly and insignificantly lower in exposed children. When the confounding factors were taken into account, the prevalence of symptoms at schools within 1-3 km from the fertilizer production was marginally higher. These findings give no support to the hypothesis that fertilizer emissions cause respiratory disease in children although an adverse effect in a few sensitive children cannot be ruled out.

[Bronchial reactivity during continuous and interrupted exposure to respiratory irritants]. / Reaktivnost bronha u toku kontinuirane ekspozicije respiratornim iritansima i izvan nje.

Evolution of bronchial reactivity was examined in a sample of aluminium potroom workers exposed to a variety of respiratory irritants in concentrations below the MAC values for Yugoslavia (hydrogen fluoride, particulate fluorides, sulphur dioxide). Lung function indices and bronchial reactivity were measured in 24 workers continuously employed in an aluminium plant and in nine workers who had ceased to work in the plant. Measurements took place over a two-year interval. A sustained level of bronchial reactivity was recorded in both examined groups regardless of occupational practice. Even in workers with dyspnoea and airway obstruction bronchial reactivity did not worsen in spite of continuous exposure. Avoidance of exposure to potroom fumes did not bring about any significant improvement of reactivity, moreover, bronchial reactivity deteriorated in one worker. Owing to discordance between spirometric values and bronchial reactivity, a follow-up of workers removed from harmful occupational exposure is suggested.

[Biological effects of nonionizing radiation: low frequency electromagnetic fields]. / Bioloski ucinci neionizirajuceg zracenja: elektromagnetska polja izrazito niskih frekvencija.

This article reviews various studies on effects of electric and magnetic fields of extremely low frequencies on human health and gives an overview of residential and occupational exposure to different sources, currently established exposure limitations, and protection measures. Throughout the evolution biological systems adapted to natural electric and magnetic fields. Only hundred years ago human exposure to radiation was limited to electric and magnetic fields arising either from extraterrestrial or terrestrial sources, yet both natural. For the past fifty years there has been large growth of artificial sources of electric and magnetic fields, especially with frequencies of 50 and 60 Hz (power generating and distribution systems). The concern about long-term exposure to artificial fields and possible adverse effects on human health has been entirely justified and led to numerous intensive epidemiological and laboratory studies. Results of several epidemiological studies confirm the connection between exposure to electric and magnetic fields of extremely low frequencies (up to 300 Hz) and increased risk of leukemia and brain tumor in children and adults. In addition, the risk of breast cancer in occupationally exposed population has increased. Laboratory studies on animal models, in vitro systems, and human volunteers did not confirm this connection. There is a growing interest in investigation of other possible adverse health effects such as neurodegenerative diseases (Alzheimer's disease and other forms of dementia, amyotrophic lateral sclerosis), cardiovascular disorders (arrhythmias and acute myocardial infarction), psychiatric disorders, and electrosensitivity.

Alpha 1-antitrypsin and lung function in cement workers.

The relationship between the serum concentration of alpha 1-antitrypsin (AAT), the concentration of dust at the workplace and lung function abnormalities was examined in 48 male workers occupationally exposed to cement dust. Measurements were performed in all subjects and included ventilatory volumes (FVC, FEV1), airway resistance (Raw), static lung volumes (RV, FRC, TLC), transfer factor for CO and AAT serum concentration. The relationship between lung function, smoking, respirable cement dust exposure, and AAT serum concentration was investigated by the method of multiple linear regression. A statistically significant correlation was observed between AAT blood concentration and respirable dust exposure. The contribution of respirable dust exposure to the description of AAT concentration was positive as was the contribution of Raw. The contributions of transfer CO, smoking and RV/TLC ratio were negative. All the variables considered accounted for approximately 30% of the total variability of the AAT concentration. To conclude, in cement workers the higher AAT serum concentration which is associated with a loss of lung function, and higher respirable cement dust concentration may be part of the defence mechanism against the potential proteolytic activity occurring in occupational dust exposure.

Respiratory impairment among children living in the vicinity of a fertilizer plant.

The study included 162 second-grade children (85 boys and 77 girls) aged 8-9 years, attending two schools in an area with a fertilizer production plant, and 59 second-graders of the same age (32 boys and 27 girls) from a small neighbouring town located 20 km west of the plant, without any particular source of pollution. During the period from December 1990 to May 1991 the incidence of acute respiratory diseases was surveyed in children and their family members, and forced expiratory volumes were measured in selected second-graders in December 1990 and April 1991. In the area with the fertilizer plant as well as in the compared area ammonia, hydrogen fluoride, nitrogen dioxide, total suspended particulate matter and smoke were measured daily in ambient air and inside the school buildings. The mean concentrations of pollutants during the study period were below the recommended limits, with only a few exceptions, but daily fluctuations, particularly of ammonia and hydrogen fluoride in the area around the plant happened to exceed these values. The observed differences in the levels of air pollution correlated to some extent with the health parameters followed up during the study period. The incidence of acute respiratory diseases corresponded to the registered differences in the exposure to measured pollutants. Forced expiratory volume values in the compared groups of children did not consistently reflect the differences in exposure levels.

Bronchoconstriction in potroom workers.

The effect on airway responsiveness of an oral dose of a beta-adrenergic blocker (80 mg propranolol) given before work, was studied in 15 potroom workers who complained of dyspnoea, chest tightness and wheezing after they had started to work in potrooms. The same study was performed in a group of 10 potroom workers, selected at random, who had not complained of such symptoms. In addition, another group of 12 potroom workers with respiratory symptoms were given 1 mg atropine subcutaneously. Ventilatory function was assessed from forced expiratory curves (by means of a waterless spirometer) and from maximum expiratory flow-volume curves (by means of a digital pneumotachograph). Bronchoconstriction during the first few hours' work was significantly potentiated by propranolol in the group of potroom workers with respiratory complaints. Propranolol did not produce this effect in workers who had not complained of respiratory symptoms. Atropine sulphate abolished the fall in ventilatory volumes which occurred during the first few hours of work. These findings suggest that acute bronchoconstriction, particularly in small airways, and respiratory symptoms occurring in certain potroom workers may be based on an alteration in autonomic balance with vagal preponderance.

Case report of occupational asthma due to palisander wood dust and bronchoprovocation challenge by inhalation of pure wood dust from a capsule.

Occupational asthma due to exposure to exotic wood dust and to rosewood (Dalbergia family) has been reported earlier. This paper deals with a case of occupational asthma due to palisander wood dust (Dalbergia nigra) in a joiner who sanded and polished parts of musical instruments. The causal relationship was confirmed by a positive skin reaction to an allergenic preparation and a positive nonimmediate, late asthmatic reaction after inhalation challenge testing with pure palisander wood dust. A method of bronchoprovocation testing with an occupational allergen is presented. It proved to be a practical and advantageous method in its simplicity and single-blind application of placebo. It should, however, be used with great caution, in well-chosen cases in whom nonspecific bronchial reactivity is proved or recorded to be in normal ranges.

The role of atopy in potroom workers' asthma.

A study was performed to clarify a possible role of atopy in the occurrence of acute bronchoconstrictive impairment observed in some workers in a plant using the Alu-Swiss process for the electrolytic extraction of aluminum. Of 227 workers examined the percentage of those with a history of atopy and positive skin tests for common allergens was within the expected range. Six had positive patch test with 2% NaF. Among seven workers with paroxysmal wheezing and dyspnea, of whom three were only light smokers, three had positive skin test with common allergens but only one of them had an increased IgE value. The same worker also had positive patch test for 2% NaF. The average age of workers with paroxysmal wheezing and dyspnea was 32.6 years, and only two had symptoms defined as chronic bronchitis. Although their forced expiratory volumes, with two exceptions, measured at the beginning of work shift were within normal limits, in most of those workers bronchial hyperreactivity was also objectively assessed using nonspecific bronchoprovocative tests with histamine (or metacholine). The results support our previous findings that acute respiratory impairment in some workers is most probably based on bronchial hyperreactivity and not on an allergic mechanism.

Anthropometric and physiological properties in the determination of biological distances.

The investigation of anthropometric dimensions of the body and head, lung function tests and blood pressure was carried out in 3 separate groups. The analysis of 'distances' between particular pairs of the analyzed groups was performed by Penrose's CH2 and its components CQ2 and (v-l/v)CZ2. It is pointed to various ways of diversification of particular characteristics, which is likely to depend on different selective inertia of particular traits, that is, on different intensity of the effect of genetic and/or ecological factors on their formation. It is shown that as many different biological characteristics of human groups as possible should be taken into consideration for the calculation of 'distances'.

Occupational histamine poisoning by fish flour: a case report.

Histamine poisoning due to inhalation and skin contact with fish products is rarely described in the literature. This study presents a case of occupational histamine poisoning by spoiled fish flour via inhalation, skin and eye contact. Shipments of fish flour transported in black or blue bags, depending on the source, were handled by 20 harbour workers. Ten workers handling blue bags developed allergy-like skin, eye, gastrointestinal, respiratory and cardiac symptoms within 30 min. Workers handling black bags were symptom-free, except for minimal eye irritation. After consultation with the Poison Control Centre histamine poisoning was suspected. The histamine content, as determined by thin-layer chromatography, was 10-fold higher in samples from the blue than from the black bags (510 mg/100 g flour compared with 50 mg/100 g flour, respectively). Part of the shipment was labelled as hazardous for human health with permission for further usage only under specific personal protective measures. It is suggested that the highest permissible levels of histamine in fish flour and similar products should be set and legally adopted.

Assessment of colour vision impairment in male workers exposed to toluene generally above occupational exposure limits.

We investigated colour vision impairment in 45 male workers occupationally exposed to toluene (mean value of toluene concentration in ambient air = 119.96 ppm) and in 53 controls. Colour vision was evaluated by Lanthony-D-15 desaturated test and expressed as Age and Alcohol Intake Adjusted Colour Confusion Score (AACDS) or types of dyschromatopsia. Exposure was evaluated by measurement of toluene concentration in ambient air and blood, and hippuric acid and orthocresol determined in urine after the workshift. A statistically significant higher AACDS value was established in the exposed subjects compared to the controls (p < 0.0001). There was no significant difference between AACDS values on Wednesday morning compared to Monday morning. In the exposed group AACDS significantly correlated with the concentration of toluene in ambient air, concentration of toluene in blood and the concentration of hippuric acid in urine after the workshift (all p < 0.0001). Dyschromatopsias were detected in both groups, although no significant difference between groups was established. In the exposed group concentration of toluene in ambient air, alcohol intake and age explained 35.1%, concentration of toluene in blood, age and alcohol intake explained 19.9%, and concentration of hippuric acid in urine and age explained 19.2% of the variation in type III dyschromatopsia. Concentration of toluene in ambient air and age explained 28.3% of the variation in total dyschromatopsia, and concentration of hippuric acid and age explained 13.8%. In the control group, age and alcohol intake explained 19.6% of the variation in type III dyschromatopsia. In exposed workers a significant difference was found in the AACDS value compared to controls. However, no significant difference was found in the prevalence of colour vision loss in the yellow-blue and/or red-green axis. Based on the results of this study the authors conclude that the effect of toluene on colour vision can be chronic and that the possible reparation period in colour vision impairment is longer than 64 hours.