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Biomedical subjects

F Valić

Publications and source records attributed to F Valić.

At least 19 recordsLinked to original sources
PubMed1996

Are chlorine-free compounds a solution for health problems caused by ozone-depleting substances?

In January 1996, the Government of Croatia and United Nations Environment Programme (UNEP) signed an agreement on the phasing out of ozone-depleting substances in Croatia, making the problem of identifying adequate substitutes a high priority. In this paper, the main ecologic characteristics of chlorine-containing fully halogenated chlorofluorocarbons (CFCs) and partially halogenated chlorofluorocarbons (HCFCs) compared with chlorine-free hydrofluorocarbons (HFCs) are presented. The data showed HCFCs to be ecologically more acceptable than CFCs, particularly regarding the ozone-depleting potential (ODP), and have therefore been proposed as substitutes for CFCs. However, although having lower ODP, long-term they could still harm the stratospheric ozone layer, and are therefore hardly acceptable. HFCs are promising substitutes which, having no chlorine, have no ODP. Six were toxicologically evaluated; three of them were found flammable. Toxicological characteristics of three nonflammable compounds (HFC 125, HFC 134a and HFC 227ea) are presented. Their toxicity, not yet completely evaluated, appears to be low.

Animals↗
PubMed1996

[Byssinosis--an occupational disease of textile workers].

Byssinosis as a nonspecific chronic respiratory disease in textile workers exposed to cotton, hemp and flax is described. Pathogenesis and ethiologic factors responsible for bissynosis are listed. Clinical symptoms of byssinosis and differential diagnosis with occupational asthma are presented. Characteristic functional changes of ventilatory capacity in textile workers are described. Clinical and functional criteria for diagnosis of byssinosis are presented. Particular emphasis is given to preventive medical and technical measures in order to prevent the development of respiratory diseases in textile workers.

Byssinosis↗
PubMed1993

Is chrysotile asbestos exposure a significant health risk to the general population?

The main unresolved issues concerning environmental exposure to chrysotile asbestos of the general population are discussed. A review of the results of the measurement of airborne chrysotile fibres in buildings is presented showing that the results have been consistently low with the exception of buildings with damaged friable asbestos-containing material. Quantitative risk assessments are presented indicating that the lifetime risk is small compared to many other environmental risks. Possible adverse health effects of paraoccupational exposures in the case of high domestic airborne asbestos levels cannot be excluded. Both on the basis of electron microscopy analyses of asbestos exposures at locations with heavy traffic, and the very shallow slopes in the exposure-response relationships for increased lung cancer risk, the conclusion is drawn that exposure to airborne asbestos-containing friction materials has not been proven to pose a significant health risk to the general population. Reviewing animal ingestion studies published and all the available epidemiological studies related to asbestos in drinking water, the conclusion is drawn that the carcinogenic risk in the general population is low even in the case of drinking water containing elevated concentrations of chrysotile asbestos.

Asbestos, Serpentine↗
PubMed1992

Interconvertibility of asbestos fibre count concentrations recorded by three most frequent methods.

Simultaneous airborne chrysotile asbestos fibre samples were collected with three types of instruments, namely, the konimeter, the thermal precipitator and the membrane filter, in four asbestos plants (textile manufacturing, asbestos cement production, mining, milling). Linear regression analyses were performed of the membrane filter on the konimeter and thermal precipitator count concentrations, respectively. Sampling was performed at 24-35 locations in each of the processes studied. In order to linearize the relationships and to stabilize the sample variances the data were transformed using the transformation ln(x+1) for both the predictor and the response variables. Eight linear regression equations were developed. The slope coefficients of regressions differed significantly (P < 0.05 or < 0.01) between all the asbestos processes except for the differences of coefficients in mining and milling (P > 0.05). It is concluded that no single conversion factor can be used to reliably convert the konimeter or thermal precipitator to membrane filter asbestos fibre concentrations; a separate conversion factor must be derived for each technological process. In this case the confidence limits of estimates are acceptable for practical occupational hygiene purposes.

Air Pollutants, Occupational↗
PubMed1991

Relationship between cumulative occupational exposure to asbestos fibres and respiratory symptoms.

A survey of chronic respiratory symptoms was undertaken in 1127 asbestos workers engaged in asbestos mining, asbestos cement production, production of friction materials or in the manufacture of asbestos textile. A control group of 593 persons was also surveyed. The exposure of asbestos workers was analysed by evaluating separately the cumulative exposure to total airborne particles and to airborne asbestos fibres. The prevalences of all the respiratory symptoms (chronic cough, chronic phlegm, chronic bronchitis, dyspnoea grade 3+) were significantly higher in asbestos workers compared to controls in both nonsmokers and smokers (p less than 0.01). The prevalences of all the respiratory parameters in asbestos workers increased with both the length of employment and cumulative exposure to total airborne particles. Prevalences of chronic cough, chronic phlegm and chronic bronchitis did not show an increase with cumulative exposure to airborne asbestos fibres expressed as fibres/cc years. It is concluded that the development of chronic cough, chronic phlegm and chronic bronchitis in asbestos workers is likely to be an unspecific effect of the exposure to the difficulty soluble airborne particles rather than a specific effect of the exposure to airborne asbestos fibres.

Adolescent↗
PubMed1990

[Is it necessary to remove fibrous insulation material from buildings?].

Because of potential negative health effects of exposure to airborne fibres, removal of fibrous insulating materials from buildings, particularly asbestos, has become a frequent, in many cases unjustified, undertaking. The results are presented of the determination of airborne mineral respirable and non-respirable fibres, fragments and total airborne dust in a public building before the substitution of the insulating material, shortly after, and about two months later. There were no differences (P greater than 0.05) between the mean concentrations of respirable fibres (diameter less than or equal to 3 microns, length greater than or equal to 5 microns, aspect ratio greater than or equal to 3:1) measured before (0.0038 and 0.0031 f/cm3, resp.) and about two months after (0.0038 and 0.0028 f/cm3, resp.) the substitution, suggesting that the substitution was unnecessary. However, the concentrations measured two and eight days after the substitution were significantly elevated (P less than 0.05; P less than 0.01, resp.), indicating that the unnecessary disturbance of the insulating material caused an increase of exposure levels of the employees. It is concluded that the removal or substitution of fibrous insulating materials, solely on the basis of their presence in the buildings, is unjustified. The decision should be based on elevated concentrations of airborne fibres objectively quantified. Unnecessary substitution brings about an increase, not a decrease, of the concentrations through a shorter or longer period of time.

Air Pollutants↗
PubMed1990

Ventilatory lung function changes in family members of asbestos workers.

A group of 114 adult family members of asbestos workers were examined for the prevalence of chronic nonspecific respiratory symptoms and ventilatory function changes. There was no difference in the prevalence of any respiratory symptom between the examinees and the matching members of the general population in the study areas. No difference was found between the measured and predicted values of FVC or FEV, or FEF50 in either smoking or nonsmoking men (P greater than 0.05). In contrast, all the measured values in women were significantly lower (P less than 0.0001) than their normal predicted values. Airborne chrysotile weight concentrations in five houses of asbestos workers were found significantly higher than those in four houses without inhabitants occupationally exposed to asbestos.

Asbestos↗
PubMed1981

Immunological and respiratory changes in coffee workers.

Immunological status and respiratory function were studied in a group of 45 coffee workers. Skin tests with coffee allergens demonstrated the highest percentage of positive reactions to dust collected during emptying bags (40.0%), followed by dust of green (12%) and then roasted coffee (8.9%). Among 34 skin-tested control workers, 14.7% had positive skin reaction to dust collected during emptying bags, but none had positive skin reaction to green or roasted coffee. Serum levels of total IgE were increased in 24.4% of coffee workers and in 5.9% of control subjects. The prevalence of all chronic respiratory symptoms was significantly higher in coffee workers than in control subjects. Coffee workers with positive skin tests to coffee allergen had a significantly higher prevalence of chronic cough (63.6%) and chronic phlegm (72.7%) than those with negative skin tests (32.4% and 23.5% respectively). There was a significant mean decrease over the Monday work shift in the maximum expiratory flow rate at 50% of vital capacity (MEF50: -7.9%) and at 25% vital capacity (MEF25: -17.8%), suggesting an obstructive effect mostly in smaller airways. Coffee workers with positive skin tests to coffee allergens had larger acute reductions in flow rates than those with negative skin tests but the difference was not statistically significant.

Adult↗
PubMed1979

Respiratory function in coffee workers.

Respiratory function was studied in three groups of workers employed in processing coffee. The prevalence of almost all chronic respiratory symptoms was significantly higher in coffee processors than in control workers. In each group during the Monday work shift there was a significant mean acute decrease in the maximum expiratory flow rate at 50% vital capacity (VC), ranging from 4.0% to 8.7%, and at 25% VC, ranging from 6.0% to 18.5%. Acute reductions in FEV1.0 were considerably lower, ranging from 1.3% to 2.8%. On Thursdays the acute ventilatory function changes were somewhat lower than on Mondays. Acute decreases in flow rates at low lung volumes suggest that the bronchoconstrictor effect of the dust acts mostly on smaller airways. Administration of Intal (disodium cromoglycate) before the shift considerably diminished acute reductions in flow rates. A comparison of Monday pre-shift values of ventilatory capacity in coffee workers with those in controls indicates that exposure to dust in green or roasted coffee processing may lead to persistent loss of pulmonary function.

Adult↗