Time-of-flight secondary ion mass spectrometry of matrix-diluted oligo- and polypeptides bombarded with slow and fast projectiles: positive and negative matrix and analyte ion yields, background signals, and sample aging

Human angiotensin II, chain B of bovine insulin, and porcine insulin were determined by time-of-flight secondary ion mass spectrometry under impact of approximately 25 keV Xe+ and SF5+ ion beams and approximately 100 MeV 252Cf fission fragments. Matrix-embedded samples, dissolved in a large surplus of alpha-cyano-4-hydroxycinnamic acid, were prepared by nebulizer spray deposition, neat samples by the droplet technique. It is shown that the status of the sample can be assessed by evaluating the matrix-specific features of the mass spectra. The beneficial effect of matrix isolation was small for angiotensin but large for the insulin samples, which did not show parent peaks from neat material. Negative ion yields under SF5+ impact were up to a factor of 50 higher than with Xe+. For positive secondary ions, the enhancement was much smaller. The mass spectra produced by slow ion beams or fast fission fragments were qualitatively similar. Quantitative differences include the following: with fast projectiles the yields were about 10-30 times higher than with slow ions, but similar for negative ion emission under SF5+ bombardment; the analyte-to-matrix yield ratios were higher with slow ions and up to 250 times higher than the molar analyte concentration; for analyte ions the peak-to-background ratios were higher using slow projectiles; the fraction of carbon-rich collisionally formed molecular ions was much higher with fast projectiles. Sample aging in vacuum for up to five weeks strongly reduced the yield of protonated analyte molecules ejected by slow ion impact, but not of deprotonated species. Hence protonation seems to correlate with sample "wetness" or the presence of volatile proton-donating additives.

[Incidence of occupational diseases in Poland]

The paper is aimed at presenting the incidence of occupational diseases in Poland. The analysis was performed on the basis of the information included in 'occupational disease certificates'. All sanitary and epidemiological stations throughout the country are committed to send these certificates to the Central Register of Occupational Medicine in The Nofer Institute of Occupational Medicine in Lódź. The incidence of occupational diseases during the three recent years (1996-97-98) was the subject of a thorough analysis. In all, 11,318, 11,685 and 12,017 cases of occupational diseases, respectively were registered over those three years. The corresponding rates were 116.0, 116.9 and 117.3, respectively per 100,000 people employed. In 1998, diseases of the voice organ predominated (30.4%) of all occupational diseases) and they were followed by hearing impairment (28.2%), infectious and parasitic diseases (9.9%), pneumoconioses (8.2%), dermatoses (6.4%), vibratory syndrome (2.9%) and poisoning (2.5%). These disease categories constituted over 88% of all occupational diseases registered in that year. Diseases of the voice organ which showed the greatest growth dynamic were mainly diagnosed among teachers. Neither in the United States nor in the member states of the European Union, this pathology is included into the list of occupational diseases. In view of high rates of its incidence in our country it has become one of essential problems of occupational medicine. In Poland, particular attention is paid to infectious and parasitic diseases among which hepatitis occupies the first place (65%), mostly among health service workers. The decrease in hepatitis incidence observed in the 1990s has been due to an intensive vaccination programme in this group of workers. The incidence of occupational hepatitis became rather stable and accounted for 940 cases per year, however the incidence of hepatitic C increased at the same time. Lower rates of incidence of 'classic' occupational diseases, such as poisoning, pneumoconioses or vibratory syndrome are a positive observation. It is also interesting to note that the rate of occupational diseases diagnosed in advanced stage has also diminished. When analyzing occupational diseases one should bear in mind that the majority of pathologies already diagnosed result from long-term effect of exposure to harmful factors. In all, 93% of cases of occupational diseases emerged after a ten-year exposure. The highest rates, taking account of sections of activity, were found in mining and quarrying, health service, agriculture, hunting and forestry.

[Quantitative assessment of cancer risk following epidemiological studies]

The role of data derived from epidemiological studies in the quantitative assessment of cancer risk has been constantly growing. That results from the fact that epidemiological studies are performed directly on humans so that it is possible to avoid bias very often associated with methods of extrapolation between animals and humans. Moreover, a slow but continuous increase in the number of well designed epidemiological studies with results which can be used to estimate dose-response relationship is being observed. In this paper, the methodological foundations of cancer risk modelling on the basis of epidemiological studies are discussed, and the dose-response relationship based on epidemiological study carried out in an occupational cohort of workers employed in a pulp and paper plant was estimated. The epidemiological study was performed by the team of the Department of Epidemiology, The Nofer Institute of Occupational Medicine, Lódź. Lung cancer was adopted as the effect of occupational exposure. In oder to estimate the increase in cancer risk induced by occupational exposure, the risk for the whole occupational life was calculated by employing the methods of competitive risks, essential relative risks were modelled using Poisson means for data divided into groups, and a Cox proportional-hazards model was used for single data. The analysis indicated, that the data from epidemiological studies render it possible to carry out a more thorough investigation as compared to data obtained from animal experiments. As to the cohort under study, a certain effect of age at which workers enter into exposure on lung cancer risk was observed. A risk 'outfit' the workers bring in at the beginning of their employment is clearly visible in older age groups. A general conclusion drawn from the study may be formulated as follows: epidemiological studies play a major role in assessing the effect of working conditions on the increase in the morbidity risk, however, they are not a panacea for all the problems emerging in the cancer risk assessment in exposed persons. Therefore, information obtained from epidemiological and toxicological studies should supplement and reinforce one another, and data from both sources should be used to obtain the best possible characteristics of risk cancer in humans.

Hyposensitivity to amphetamine following exposure to chlorphenvinphos--protection by amphetamine preexposure

We investigated the effect of an acute exposure to chlorphenvinphos (CVP), an organophosphate anticholinesterase, on amphetamine-induced open-field locomotion in rats. CVP was administered in a single i.p. dose of 1.0 mg/kg (1/10 of the LD50). All animals were challenged with 1.0 mg/kg amphetamine (AMPH) three weeks after the CVP exposure, i.e. after a time sufficient for acetylcholinesterase recovery. Some rats were also given AMPH three weeks before the CVP exposure. In rats challenged with AMPH only once after the CVP exposure, AMPH-induced open-field locomotion was significantly reduced. Such an effect was not observed in rats given AMPH three weeks before the CVP exposure. The results suggest that a single CVP exposure may result in persistent dopaminergic hyposensitivity, and that an amphetamine pretreatment may protect the rat against this effect.

[The causes of increased risk for lung cancer in the pulp and paper industry workers. The effect of smoking and exposure to chemicals]

An analysis of mortality in a cohort of workers employed in the pulp and paper industry, carried out by the authors of this presentation several years ago, indicated an increase of 22% in the risk of mortality from lung cancer. This risk decreased by only 4% after taking account of smoking. The results obtained then were considered as sufficient to undertake further studies aimed at identifying specific occupational factors responsible for an increased risk for mortality from lung cancer in the population under study. The nested case-control study, in which cases (of lung cancer) and controls were selected from the same cohort observed earlier, was approved as the most suitable method for achieving the aforesaid aim. The study covered 79 cases of deaths from lung cancer confirmed by histological and cytological or radiological examinations, and 237 'healthy' controls matched in the ratio of one to three, taking into account gender, date of birth and date of employment. A group of experts carried out in-depth analysis of exposure to harmful factors in each case of death and in each control. Using a questionnaire, specially developed for this purpose, detailed data on smoking habits among persons under study were collected. Odds ratio was used as a measure of a relative risk for death from lung cancer. A crude relative risk and risk adjusted by eliminating the effect of smoking, applying the model of conditional logistic regression, were calculated for individual exposure factors. Smoking proved to be a significant causal factor responsible for the development of lung cancer in the cohort studied. That was evidenced by relative risk accounting for 12.9 for smokers in relation to non-smokers and an enhanced risk with the increasing number of cigarettes smoked daily, the number of smoking years and an accumulated dose. The study does not confirm a hypothesis that chemical factors specific of the pulp and paper industry exert a significant effect on the risk of death from lung cancer. Odds ratios, crude and adjusted for smoking, were lower than one in all distinguished categories of exposure.

[Application of BMD models in quantitative evaluation of carcinogenic risk]

The characteristics of the relationship between the exposure level and the incidence of harmful health effects is a general objective of assessing health risk related to chemical exposure. A real dose-response relationship, particularly for low doses, is usually unknown thus it can only be deduced on the basis of biological and statistical considerations. Low dose risk estimation requires extrapolation beyond the range of data observed. Nowadays, quantitative risk assessment encounters certain duality as linear models are mostly used in evaluation of environmental exposure, and nonlinear models are most frequently applied in occupational exposure. Bearing in mind that the assumption on the dose-response linear relationship is an apparent simplification built on our lack of knowledge of carcinogenic mechanisms, it seems that the proposal of the US Environmental Protection Agency (US EPA) to use benchmark dose methods (BMD) for exposure effects manifested by neoplasms, is the compromise between a conservative approach of the EPA towards risk modelling resulting from the limited knowledge of these mechanisms and lack of criteria for selection of nonlinear models. In the case of carcinogenic risk assessment, this solution involves the identification of so called 'cut off point' by applying relevant statistical models. The cut off point indicates the exposure level that contributes to the increase in risk by 10%, 5% or 1%. Another possibility is to use interspecies extrapolation methods for the cut of point modification, and then draw a line between the cut off point and the beginning of the system of co-ordinates. Since it is not feasible to apply a complete BMD methods for certain chemicals (e.g. bezo(a)pirene), not because of chemical properties, but due to insufficient experimental experience, it is proposed to use the method of sticking together a straight line and a curve in relation to a two-grade curve and not to its confidence limitation.

Cancer risk in workers of the pulp and paper industry in Poland. A continued follow-up

A mortality cohort study was undertaken among Polish pulp and paper workers. This paper concentrates on neoplasms mortality among men and women employed continuously for at least one year in the factory producing sulphate pulp, paper board and paper products. A retrospective observation carried out till 31 December 1995 covered 10,460 workers employed during the years 1968-1990. The cohort accessibility was 99%. Cancer risk was evaluated on the basis of standardized mortality ratio (SMR) calculated according to the person-years method. The general population of Poland was the reference population. The results of a 23-year cohort observation, published earlier, showed a lowered overall mortality from all causes and from all malignant neoplasms, and a significant excess of death from peritoneum and prostate cancer among pulp mill male subcohort. The conclusion was drawn that a 'young' cohort and relatively short follow-up period might have affected the results. The results presented in this paper, obtained after further five years of observation showed in the male cohort an excess of deaths from cancer of respiratory tract and peritoneum (lung SMR = 122, nasal cavities SMR = 587, peritoneum SMR = 562). An approximate correction for smoking habits resulted in only 4 decreased risk estimates for lung cancer, indicating a small positive confounding effect of smoking in this material. In female cohort an excess of brain cancer was found (SMR = 355). Only the excess mortality from cancers of nose, lung and peritoneum was coherent with the exposure to higher concentrations of wood dust, pulp, paper and board dust. It may support a hypothesis that these factors as well as dust pollutants, not yet identified in this study, may be considered as one of the risk factors contributing to the incidence of neoplasms of these sites.

Environmental exposure to asbestos in asbestos cement workers: a case of additional exposure from indiscriminate use of industrial wastes

The paper presents data on cancer risk, especially pleural mesothelioma and lung cancer, among the workers of asbestos cement plant who living in the vicinity of the plant, were also environmentally exposed to asbestos. In 1959 an asbestos cement factory was founded in the rural area of south-eastern Poland. Apart from chrysotile asbestos, crocidolite was used till 1985 chiefly for the manufacture of pressure pipes. The blue asbestos made up 15% of the mean annual tonnage of the processed asbestos. It was found that soon after asbestos production had started the process wastes were made available to local community, particularly to the workers of that factory. For over twenty years asbestos wastes of all kinds, both wet (process sludge) and dry (from pipe and sheet grinding) were exploited for the hardening of roads, paths, farmyards and sports fields and as construction material components. For the evaluation of cancer risk due to occupational exposure to asbestos a cohort of 1,526 workers employed in this factory was observed till the end of 1996. The cohort availability was 95.6%. Standardized mortality ratio (SMR) was calculated using the man-years method. The reference population was the general population of Poland. The results of the study demonstrated a statistically significant increase in the risk of a) pleural mesothelioma--over an 80-fold excess among males and over a 200-fold one among females; b) lung cancer in females--over a 6-fold excess; c) colon cancer in males--over a 3-fold excess. In the 1990 ten new cases of pleural mesothelioma in the cohort were reported. As compared to other asbestos-cement cohorts in Poland, observed at the same time, this cohort presented a very high risk of pleural mesothelioma. The analysis of 16 cases of pleural mesothelioma found in the cohort from 1987 to 1997 revealed 4 cases with very short employment period (3.5 months-5 years) including two cases with relatively short latency period (11-12 years). In order to find explanation of these findings, additional investigations were made. The epidemiological study indicated that all these persons were at the same time subject to non-occupational exposure associated with massive utilization of commonly available asbestos-cement wastes as road surface material.

[Evaluation of reproductive disorders in men occupational exposed to lead]

The objective of the study was to define the prevalence of reproductive disorders in men occupationally exposed to lead in concentrations occurring usually in the work environment. The period of time preceding the conception in couples in which men were occupationally exposed to lead was adopted as the measure of the disorder. A cross-section survey was performed. Men of selected plants of Upper Silesia and Głogów responded to questions included in the questionnaire regarding age, education, occupation, occupational exposure, health condition, addictions, the situation in the family as well as questions concerning the respondent's spouse (age, education, occupation, addictions, health condition). The blood lead concentrations in persons exposed to this metal in the period preceding the conception were defined on the basis of medical data stored by the plant occupational outpatient clinics. The control group consisted of workers of the metallurgic industry, living in Lódź or its vicinity, and non-occupationally exposed men living in Silesia. In total 341 exposed men and 510 non-exposed controls participated in the study. The investigated groups were rather homogeneous as to the age of those under study and their spouses, education, addictions and the number of children. The analysis of the survey results indicated that in 5% of couples in the control group the time before conception exceeded one year. A similar occurrence of reproductive disorders was found in couples in which man was occupationally exposed to lead. The proportion of couples with reproductive disorders in this group (regardless of the size of Pb exposure) was 6%. The stratification of the Pb-exposed groups, taking into account the exposure size in accordance with the WHO criteria (group 1-220 micrograms/l, that is below the accepted value above which the ZnPP level increases; group II-PbB 200-400 micrograms/l that is up to the level recommended as the highest level for the population occupationally exposed to lead; and group III-PbB above 400 micrograms/l) allowed the analysis of the frequency of reproductive disorders depending on the size of the exposure. The percentage of couples with delayed conception accounted for 4.5% in group I; 8.7% in group II, and in group III did not differ significantly from that in the control group. These results show that men's occupational exposure to lead below allowable concentration in the biological material (500 micrograms/Pb/l blood in Poland or 400 micrograms/Pbl recommended by WHO) does not pose the risk for prolonged period preceding the conception in their partners.

[Data processing computer system for evaluation of health effects due to occupational diseases diagnosed in Poland]

General consequences of occupational diseases for both employees and the country's economy have been known for many decades. Nevertheless there were no legal instruments and financial means to carry out studies leading to a comprehensive evaluation of health effects induced by occupational diseases diagnosed in Poland. Only recently, the legal basis has been provided by the revision of the regulations on occupational diseases (Official Journal of the Ministry of Health and Social Welfare no 9, heading 51, 1989), and the financial means allocated according to the Governmental Strategic Programme (SPR-1) for the years 1995-1998. The objectives of the study and the results obtained have been presented in another publication. Here the authors concentrated on some aspects of data collection and their analysis. An essential element in the establishment of data base on health effects of occupational diseases was its integration, namely the number of diagnosed occupational disease had to correspond with the entity in the Register of Occupational Diseases. Such an approach helped to avoid including in the base all metrical data, as information on effects of occupational diseases was collected exclusively for persons with detected and diagnosed occupational disease, which had to be previously placed in the Register of Occupational Diseases. The correctness of data input and the data analysis were carried out outside the Paradox system. The analysis of histograms of characteristics under study and the explanation of departing values were employed to evaluate the freedom from bias, and the statistical package for social sciences (SPSS) was used to analyse the data.

[Health effects of occupational diseases diagnosed in Poland during the years 1990 and 1994]

The study was carried out on the material of 15,136 occupational diseases that accounted for 71.9% and 65.6% of all cases detected in 1990 and 1994, respectively. The analysis focused on the selected health effects of occupational diseases, such as sickness absenteeism, the transfer to other workposts, the percentage of health impairment and related single recompensation as well as disability pension. The study helped to draw many conclusions of great value, and disclosed major pathologies and their causes responsible for the range of related health effects. Long-term sickness absenteeism, high percentage of health impairment and related consequences for the country's economy (single recompensations and growing number of disability pensions paid due to occupational diseases), and low proportion of transfers to safe workposts were most striking among the effects in question. The study also contributed to initiating the establishment of the data base and the development of the system for data collection and analysis of information on health effects of occupational diseases in Poland.

[A quantitative assessment of health risk induced by occupational exposure to inorganic arsenic]

The risk of neoplastic disease, primarily lung cancer, induced by occupational, inhalation exposure to nonorganic arsenic was assessed. In order to identify individual risk in the linear dose-response relationship which would serve as a basis for the risk assessment among persons exposed occupationally, the author also analysed the latest epidemiological studies performed in Sweden, as well as repeated analyses of American studies. This allowed to diminish individual risk by several times. It is thought that a diminished value of individual risk is, in the light of the most up-to-date epidemiological studies, closer to the reality than the value proposed by the Environmental Protection Agency (EPA). Having the value of individual risk related to occupational exposure, equal 1.79 x 10(-4), lung cancer risk after forty years of employment under the exposure level within the range of currently binding MAC values for arsenic (0.05 mg/m3) accounts for 8.95 x 10(-3), thus slightly exceeding the adopted value of 1 x 10(3). Whereas a new value, proposed by the Expert Group for Chemical Factors of the International Commission for Updating the list of MAC and MAI values in 1996, equals 0.01, so the risk for a forty-year employment accounts for 1.79 x 10(-3), in fact the value corresponding to that already approved. In addition, the assessment indicated that smoking increases by 4-6 times the risk of lung cancer induced by exposure to arsenic.

[Cancer risk in asbestos-cement industry workers in Poland]

A cohort study was carried out in order to evaluate the cancer risk in the asbestos-cement industry workers. The cohort consisted of workers employed in four asbestos-cement plants. One of those plants was established in 1924, the other three in the 1960s and 1970s. Currently only two of these plants continue their production. The plants used mainly chrysotile asbestos as well as crocidolite and amosite. Amphibolite asbestos was used before the mid-nineteen eighties in production of pressure pipes utilising about 15% of the total quantity of asbestos used. The measurements of the asbestos fibre concentration at work-sites have been taken occasionally since the mid 1980s, thus, the determination of a cumulative dose for individual persons in the cohort and the evaluation of the dose-effect relationship were not feasible. It could only be supposed that the concentrations at the preparatory work-site during first years of the plants' operation accounted for several tens fibres/cm3 in the production that employed the dry method. The cohort consisted of workers employed in the plant for at least three months between beginning of the plant during the post-war period, and 1980, that is during the period when amphibolite asbestos was in use. The retrospective observation was completed on 31 December 1991. The analysis of the death risk by causes was based on a standardized mortality ratios (SMRs) calculated using the person-years method. Statistical significance of SMRs was assessed by means of Poisson distribution one-sided test. The general population of Poland was used as the reference population to estimate the death risk. The cohort comprised 4,712 persons (3,563 males and 1,149 females). Of this number 4,500 persons (3,405 males and 1,095 females) were followed. The cohort availability were 95.5%. Male mortality, both total (473 deaths; SMR = 83) and due to malignant neoplasms (108 deaths; SMR = 86) was lower than in the general population. An excess of deaths from neoplasm of the pleura was by about 23 times higher (5 deaths; SMR = 2,288) and from neoplasm of the large intestine by two times higher (7 deaths; SMR = 214). Among females (41 deaths; SMR = 50) death risk was lower than in the reference population. At a low level of total mortality from neoplasms (13 deaths; SMR = 52) a statistically significant excess of deaths from neoplasm of the pleura (2 deaths; SMR = 2,112) was observed. In the plants investigated the analysis revealed a considerably diversified mortality from asbestos-related neoplasms. The incidence of pleura mesothelioma should be attributed to the use of considerable quantities of crocidolite asbestos and high concentrations of fibres in the air in plants II and IV, particularly during the first years after their establishment. In view of a long period of latency the excess of this neoplasm can be expected till 2020.

[The effect of occupational exposure to metallic mercury on selected parameters of hemostasis]

The group investigated comprised 60 workers under conditions of chronic exposure to metallic mercury vapours (mean exposure duration--9.3 yrs; mean age of subjects--38.5 yrs). The control group was composed of 24 non-exposed persons (mean age--39.9 yrs). The workers exposed were divided into three groups according to the air concentration of metallic mercury vapours at the workpost, group A--0.15-0.17 mg/m3, group B--0.03-0.08 mg/m3 and group C--0.02-0.03 mg/m3. The workers qualified for the study did not receive any medication containing acetylsalicylic acid derivatives, and did not consume alcoholic drinks for few days prior to the study. Persons with the diagnosis or the history of blood disorders, venous or arterial thrombosis as well as those with diabetes and hyperlipidaemia were excluded from the study. The haemostasis assessment was based on the results of laboratory tests, PLT, TBT, ACT, APTT, HTCT, INR and Fg, AT III, alpha 2 M, FDP, and FM concentrations. The comparison of the exposed and control groups revealed a statistically significant decrease in ACT and AT III concentrations. When particular groups under exposure were compared with one another and the controls, the increased INR and Fg concentrations were found in group A. Moreover, this group showed an increased platelet count, as well as decreased TBT and alpha 2 M concentrations. However, the differences between the groups were statistically insignificant. The results of the study indicated that chronic exposure to mercury may impair haemostasis and lead to hypercoagulability. The latter may result from the deficiency of natural coagulation inhibitors.

[Mortality among workers in the pulp-paper industry. A successive follow up of the cohort]

After five successive years of observation the authors present a verified evaluation of the delayed health effects in the pulp and paper industry workers (with particular regard to mortality from malignant neoplasms). The cohort studied consisted of 10,460 workers employed for at least 12 months between 1967 and 1990 in the plants manufacturing sulfate pulp, paper, board and paper products. Subjects were assigned to three subcohorts according to the work areas: 1. pulp mill workers; 2. paper mill workers (paper and board as well as their products); 3. other workers. The workers were enrolled in the subcohort if they were employed for at least one year in one of these departments. One subject could be included in more than one subcohort. The vital status of the cohort was determined through a variety of sources over an observation period of 28 yrs (1967-95). Mortality data were analysed in terms of cause-specific standardized mortality ratios (SMRs) with expected deaths count based on the national mortality rates in Poland. The results of a twenty three-year cohort observation, published earlier, showed the lowered overall mortality (explained by a "healthy worker effect") and the excess of deaths from malignant neoplasms for some sites (peritoneum, prostate, brain). Due to a small number of deaths recorded, kind of exposure and its duration, were left out of the analysis. The results presented in this paper, obtained after five successive years of the male cohort observation, showed an excess of deaths from cancers of the respiratory tract and peritoneum. In the female cohort an excess of brain cancers was found. Only an excessive mortality from malignant neoplasms of the respiratory system was coherent with the exposure to higher concentrations of wood, paper and board dust. An excess mortality from diseases of the circulatory system was found in both males and females employed in paper production.

[Morbidity of occupational diseases in Poland in the years 1994-1996]

The authors analysed all cases of occupational diseases diagnosed in Poland over the last three years. The following variables were considered: age, gender of patients, duration of exposure to factors inducing occupational disease, nosologic units, and the types of work places by the European Activity Classification and their localization by voivodships. The obtained results helped to formulate the following conclusions: 1. The number of occupational diseases in the period under study ranged annually between 11,156 and 11,320 cases. The incidence rates (number of cases/100,000 employed) fell within 116-131. 2. The general incidence of occupational diseases was shaped by: hearing impairment, chronic diseases of voice organs, communicable and invasive diseases, pneumoconioses, skin diseases, vibratory syndrome and poisoning. 3. The majority of diagnosed diseases occurred at least after 10 years of occupational exposure to causal factor. 4. The highest incidence of occupational diseases by the European Activity Classification was observed in mining and quarrying, manufacture, education and health services. 5. The analysis of the occupational disease incidence in individual work places indicated a number, however small, of enterprises which are a major source of these diseases.

Heart rate variability in workers exposed to carbon disulfide

It is assumed that the cardiovascular impairments resulting from CS2 exposure may be associated with some functional disturbances within the autonomic nervous system. We adopted the heart rate variability (HRV) analysis to investigate the sympathetic and parasympathetic functions of the autonomic nervous system in workers exposed to carbon disulfide. The studies were performed on 152 workers, aged 24-66, with the period of exposure ranging from 5-38 years and 93 age-matched, non-exposed, healthy individuals as the control group. The HRV analysis concerned time-domain (AVG R-R, SD R-R, modal, median, minimum and maximum values) and frequency-domain indices (power spectrum in the very low-VLF, low-LF and high-HF frequency bands) calculated using the fast Fourier transformation. In the exposed group, neurovegetative regulation impairments could be observed. They were expressed as increased heart rate at rest, reduced power spectrum: total (TPS) and within HF, LF and VLF frequency bands as well as the absence of the physiological dependence of HRV parameters on age. These abnormalities could be found even in the group of workers exposed to the lowest CS2 levels (0-10 mg/m3) and they concerned the VLF band. In workers under conditions of exposure to 10-18 mg/m3 the dysfunction of the autonomic control referred both to its sympathetic and parasympathetic part and was found to be more intense in workers exposed to the highest CS2 concentrations (over 18 mg/m3). In view of our findings we concluded that occupational exposure to carbon disulfide may bring about an impaired neurovegetative regulation of the cardiovascular function.

[Quantitative evaluation of health risk associated with occupational inhalation exposure to vinyl chloride at production plants in Poland]

Vinyl chloride is classified by the IARC in group 1-human carcinogens. In Poland occupational exposure to vinyl chloride is found among workers employed in many branches of industry, among others in the industry of vinyl chloride synthesis and polymerization as well as in the plastics, footwear, rubber, pharmaceutical and metallurgical industries. Concentrations observed range from the noon-determinable level to 90 mg/m3, at the MAC value equal to 5 mg/m3. Neoplasm of liver is a major carcinogenic effect of vinyl chloride. Hence, the health assessment focused on this critical risk. Four different linear dose-response models, developed by several authors and based on results of different epidemiological studies, were used to characterise the extent of cancer risk depending on the level of vinyl chloride concentrations. The estimated risk related to a forty-year employment under exposure equal to MAC values (5 mg/m3) fell within the range from 2.9.10(-4) to 2.6.10(-3). As the figures depict it did not exceed the acceptable level (10(-3)).

[A qualitative evaluation of health risk associated with occupational inhalation exposure to cadmium in production plants in Poland]

In Poland several thousand people work under exposure to cadmium with different concentrations. The concentrations observed range between the level which is not determinable and the level above 0.3 mg/m3, at the MAC value equal to 0.04 mg/m3. In 1993 the cadmium classification was modified by the International Agency for Research on Cancer (IARC). Previously cadmium had been proved to be carcinogenic to animals (group 2B). At present it is classified in group 1, namely in the group of substances proved to be carcinogenic to humans. The cadmium MAC value, mandatory in Poland, has been set on the basis of the data on its chronic, toxic renal effects, but its critical effect in the form of cancer has not been taken into consideration. The author, using the results of epidemiological studies carried out by Thun et al., presented three dose-response functions which describe the relationship between the size of exposure and the probable incidence of lung cancer. The author used a linear multistage model, a Poisson model and a Cox proportional-hazards model; the magnitude of the risk from occupational exposure to concentrations equal to MAC values (0.04 mg/m3) was different for each model and it accounted for 9.02 x 10(-3), 2.04 x 10(-2) and 4.68 x 10(-2), respectively. Each of these values exceeded the acceptable level of the risk from occupational exposure which usually falls within 10(-3).

Cancer mortality among pulp and paper workers in Poland. A cohort study

Mortality among workers in the Polish pulp and paper industry was evaluated in a cohort study of 10,460 workers who had been employed continuously for at least one year, between 1968 and 1990 in the factory producing sulphate pulp, paper, board and paper products. Three subcohorts were formed according to the work areas. A standardized mortality ratio (SMR) analysis was used to compare death rates for each group exposed with Polish national rates. Mortality from all causes and from all malignant neoplasms, both in the female and in male cohorts was lower than that observed in the general population. In the pulp male subcohort a significantly elevated risk of death from peritoneum cancer (2 obs, SMR = 2,530) and prostate cancer (4 obs, SMR = 854) was recorded, although overall mortality from all causes and from all malignant neoplasms was lower than expected. The excess of deaths from neoplasms in other sites was statistically nonsignificant in all subcohorts. This study did not confirm the excess mortality from lung, stomach and lymphatic cancers found by other authors. The "young" cohort and a relatively short follow-up period (23 years) might have affected the results.

[Occupational neoplasms in Poland in the years 1971-1994]

The analysis of the incidence of malignant neoplasms, recognised as occupational disease, in Poland during the years 1971-94 was based on occupational disease certificates sent obligatory to the Nofer institute of Occupational Medicine (Lódz) by all sanitary and epidemiological stations under the Ministry of Health and Social Welfare and the Polish State Railways. During the period study 1118 occupational neoplasms were diagnosed, including 1042 cases (93.2%) of neoplasms in males. Among males malignant Ineoplasms of lung (36.1%), larynx (25.5%), bladder (14.7), skin (6%), lymphatic and haematopoietic tissue (3.4%) and pleura (2.9%) were most common. The rate occupational neoplasms in the total number of neoplasms registered accounted for 0.11% in males and 0.01% in females. PAH (29.1%), asbestos dust (18.8%), ionizing radiation (13.8%), chromium and its compounds (13.5%) and benzidine (9.8%) belong to the most frequent causes of malignant neoplasms in males, and ionizing radiation (31.5%) and asbestos dust (30.3%) in females. The number of neoplasms recognised as occupational disease is very low. Underestimation of occupational neoplasms is very common throughout the world, but it is particularly high in Poland if we take the incidence of pleura mesothelioma as an example. This is mainly due to: (1) the lack of clinical and morphological specificity of occupationally induced neoplasms; (2) a long latency; (3) the influence of other factors confounding the effect of occupational exposure; (4) a relatively small number of occupational carcinogens identified thus far; (5) limited knowledge of occupational carcinogens and criteria for occupational disease certification, and unsatisfactory interviewing skills among doctors who diagnose cancer disease. The identification of a harmful factor and the size of exposure to it, belongs to the weakest point in certifying the occupational background of the disease. The essential conclusions presented stress the urgent need for establishing the system facilitating the diagnosis and certification of occupational neoplasms.

[Eosinophil cationic protein in persons with contact allergy to disinfectants]

The concentration of eosinophil cationic protein (ECP) in blood serum was determined in 53 health service workers (women) with contact allergy to disinfectants and in 16 healthy women using a radioimmunological method. The mean ECP concentration in the study group accounted for 7.518 micrograms/l, and in the control group 4.893 micrograms/l. The concentration of 8.403 micrograms/l (the mean concentration in the control group + 2 SD) was taken as a cut off concentration value. In 17 (32.1%) persons with contact dermatitis, pathological ECP values were found. An increased ECP was observed in persons with positive results of prick test, especially in the case of Dermatophagoides, pollens and latex as well as in those with increased total IgE concentration. Our results indicate the involvement of immediate allergy in the incidence of contact allergy to disinfectants.

Mortality among different occupational groups of workers with pneumoconiosis: results from a register-based cohort study

A mortality cohort study was carried out on 11,224 men with pneumoconiosis diagnosed during the period 1970-1985. The cohort was selected from among subjects entered into the National Register of Occupational Diseases and included 7,065 coal miners, 924 employees of underground work enterprises, 1,796 workers of the metallurgical industry and iron and nonferrous foundries, as well as 1,439 refractory materials, china, ceramics, and quarry workers. The cohort was traced up to the end of 1991. The mortality of all groups enrolled in the study, as compared with that of general male population of Poland, showed a statistically significant excess of overall mortality (SMRs ranging from 105; 95% confidence interval [CI]: 100-110 to 136; CI: 121-153) as well as a great excess of deaths from diseases of the respiratory system (SMRs from 383; 95% CI: 345-424 to 588; 95% CI: 457-744). In workers of the metallurgical industry, foundries, and those from refractory materials, china, and ceramics manufacturing plants as well as quarries, a statistically significant excess of deaths from infectious diseases (mostly tuberculosis) was found (SMRs: 503; 95% CI: 364-677 and 286; 95% CI: 177-437, respectively). Mortality from lung cancer was significantly elevated only in the group of metallurgical industry and iron and nonferrous foundry workers (SMR: 159; 95% CI: 124-201). In the remaining subcohorts, no significant excess of deaths from lung cancer was noted. The study does not support the hypothesis on the role of exposure to crystalline silica in the induction of lung cancer. Significantly lower mortality was seen for diseases of the circulatory system (SMR: 89; 95% CI: 82-96), hypertensive disease (SMR: 63; 95% CI: 38-98), cerebrovascular disease (SMR: 79; 95% CI: 62-99), atherosclerosis (SMR: 79; 95% CI: 66-93), and injuries and poisonings (SMR: 50; 95% CI: 38-64) in coal miners. In addition, lower mortality was noted for cerebrovascular disease (SMR: 56; 95% CI: 32-91) and injuries and poisonings (SMR: 34; 95% CI: 17-61) in metallurgical industry and iron and nonferrous foundry workers.