Risk of fatal industrial accidents and death from other external causes among asphalt workers.

The hypothesis that asphalt workers are at increased risk of mortality from industrial accidents and other external causes was tested. Mortality rates for external and violent causes of death in a cohort of asphalt industry employees from seven European countries and Israel were compared to that of the general population. There was no evidence that mortality from external causes was increased among long term employees in asphalt application and mixing. There was an increased risk for mortality due to external causes among short term workers. However, none of the fatal accidents among short term workers appear to have occurred during employment in the studied asphalt companies. Overall, no evidence was found supporting the hypothesis that asphalt workers are at increased risk of fatal industrial or road accidents. Mortality from other external causes did not increase in this population as a whole, but increased risks among short term workers deserve further attention.

DNA-protein crosslinks and p53 protein expression in relation to occupational exposure to formaldehyde.

BACKGROUND: Formaldehyde (FA) is classified as a probable human carcinogen. AIMS: To examine DNA protein crosslinks (DPC) and p53, which are generally known to be involved in carcinogenesis, in peripheral blood lymphocytes of workers exposed to FA. METHODS: DPC and p53 ("wild type" and mutant) were examined in peripheral blood lymphocytes of 186 workers exposed to FA (mean years of exposure = 16) and 213 unexposed workers. Every worker completed a questionnaire on demographic data, occupational and medical history, smoking, and hygiene. RESULTS: The adjusted mean level of DPC in the exposed and the unexposed workers differed significantly. Adjustment was made for age, sex, years of education, smoking, and origin. Exposure to FA increased the risk of having a higher level of pantropic p53 above 150 pg/ml (OR 1.6, 95% CI 0.8 to 3.1). A significant positive correlation was found between the increase of pantropic p53 protein and mutant p53 protein, as well as between pantropic p53 >150 pg/ml and mutant p53 protein. In the exposed group a significantly higher proportion of p53 >150 pg/ml was found among workers with DPC >0.187 (55.7%) (0.187 = median level of DPC) than among workers with DPC < or =0.187 (33.3%). The risk of having pantropic p53 protein >150 pg/ml was determined mainly by levels of DPC. Workers with DPC above the median level had a significantly higher risk of having pantropic p53 >150 pg/ml (adjusted OR 2.5, 95% CI 1.2 to 5.4). CONCLUSIONS: Results suggest that DPC and mutation in p53 may represent steps in FA carcinogenesis and a possible causal relation between DPC and mutation in p53. These biomarkers can be applied in the assessment of the development of cancer due to FA exposure.

The influence of nurses' knowledge, attitudes, and health beliefs on their safe behavior with cytotoxic drugs in Israel.

The purpose of this study was to examine the influence of the nurses' knowledge, attitudes, and health beliefs on their behavior and their actual usage of safety measures while handling cytotoxic drugs in their daily work surroundings. The Health Belief Model (HBM) and its extensive form, the Protection Motivation Theory (PMT), were used as the theoretical frameworks. Sixty-one nurses participated in the study, 31 hospital-based nurses daily exposed to cytotoxic drugs for the last 5 years, and 30 non-exposed community nurses. An occupational questionnaire was used to test the nurses' actual safe behavior and compliance with the recommended guidelines. A randomly selected group of exposed nurses were observed to validate their compliant behavior. A gap was found between the nurses' knowledge and their actual behavior concerning the potential risks of cytotoxic drugs and their use of protective measures (p < .005). Significant correlations were found among the components of the extensive HBM (perceived susceptibility, barriers, benefits and self-efficacy). The observational findings supported the above results. The study's findings support the need to promote primary prevention by providing a safe environment for the employee by means of education, training with regard to safety measures, clear policy, written guidelines and their enforcement.

Frequency of sister-chromatid exchange among greenhouse farmers exposed to pesticides.

Sister-chromatid exchange (SCE) was measured in peripheral lymphocytes of 104 greenhouse farmers exposed to pesticides and 44 unexposed workers. The results of SCEs are expressed in two variables: (a) mean number of SCEs per chromosome and, (b) proportion of high frequency cells (cells with more than eight SCEs). A high correlation was found between these two variables. The adjusted means of both SCEs variables were significantly higher among the farmers compared with the unexposed group (P < 0.01). Adjustment was made for smoking, age, education, and origin. The adjusted means of both SCE variables, were significantly elevated (P < 0.05) among the farmers who prepared and applied more than 70% of the pesticides by themselves compared with those who prepared and applied less than 70% of the pesticides by themselves. Both SCEs variables were also significantly elevated (P < 0.05) among farmers who were involved in more than 7.4 sprays per year compared with those with 7.4 or less sprays per year (P < 0.05). We found a tendency towards elevation of the two variables of SCEs among those who did not use protective measures while preparing the pesticides. Evaluation of the influence of years of exposure on the frequency of SCEs showed that the two variables of SCEs were higher among those farmers who were exposed to pesticides for more than 21 years than among those with less than 21 years of exposure. The variables that had the most influence on the elevation of SCEs were self-preparation of the pesticide mixtures and the number of sprayings per year. Because the farmers used a mixture of almost 24 different chemical classes it was impossible to attribute exposure to a specific pesticide or group of pesticides to single farmers. Our finding of a significant increase of SCEs frequency in peripheral lymphocytes in greenhouse farmers indicates a potential cytogenetic hazard due to pesticides exposure.

Hematological changes in hospital workers due to chronic exposure to low levels of ethylene oxide.

We conducted a cross-sectional study to determine whether occupational exposure to low levels of ethylene oxide can cause hematological abnormalities. Blood samples were collected from a group of 47 hospital workers who were exposed to ethylene oxide during a mean period of 6.6 years (standard error, 1.1). Ethylene oxide range levels measured were < 0.01 to 0.06 ppm. The control group, individually matched by age, sex, and smoking habits, consisted of 88 workers from the administrative sector. We found significant differences between the exposed and the control group in the frequency of workers with white blood cells lower than the normal range. Although there was no significant difference in the absolute mean number of the total white blood cells, we found an elevation in the absolute mean number of monocytes and eosinophils (P < 0.01) and a decrease (P < 0.01) in the absolute mean number of lymphocytes in the exposed group compared with the control group. We also found an elevation (P < 0.01) in the percentage of hematocrit and the mean absolute number of the red blood cells, and a decrease (P < 0.01) in the mean absolute number of platelets, in the exposed group compared with the control group. The mean absolute number of eosinophils, red blood cells, and percentage of hematocrit was significantly higher, and the mean absolute number of lymphocytes and platelets was significantly lower, in the subgroups with a higher cumulative dose of exposure. A positive dose-response was found between cumulative dose exposure and the absolute mean number of eosinophils. In view of our findings, we suggest that the use of complete blood cells with differential in routine medical surveillance and for early detection of hygiene problems should be reexamined with special attention to the eosinophils count.

Impact of managers' personal determinants in notifying workplace hazards.

Notification about work hazards is a legal requirement in advanced industrial countries, but workers have claimed, that in many cases, they do not receive enough information regarding risks, exposure, and medical problems. The recent professional literature on the subject has explored the ways in which notification is delivered without sufficiently considering the psychological incentives and barriers that may affect managers in transmitting risk information. The present study aimed at examining managers' personal determinants and notification of work hazards in a sample of 106 managers and 460 workers in 40 departments of three industrial plants in Israel. Results of our study showed that both managers and workers perceived the importance of the delivery of safety information as quite high (means of 3.43 and 3.7, respectively, out of 5), with managers reporting that they rely primarily on personal modes of communication. Immediate supervisors were regarded by both groups as the most important persons in notification. Managers having past experience in treating injured workers notified more, primarily using personal notification. The most important personal determinants that positively predicted managers' notification were their sense of self-efficacy and positive expectation of notification. Outcome denial and coping by distancing were negatively correlated with notifying about these risks.

DNA-Protein Crosslinks and Sister Chromatid Exchanges as Biomarkers of Exposure to Formaldehyde.

Formaldehyde is classified as a probable human carcinogen. DNA-protein crosslinks (DPCs) and sister chromatid exchanges (SCEs) may represent early lesions in the carcinogenic process. The authors examined the DPCs and SCEs in peripheral-blood lymphocytes of 12 and 13 workers exposed to formaldehyde and eight and 20 unexposed workers, respectively. The amounts of DPCs and SCEs in the exposed and the unexposed differed significantly after adjustment for smoking. There was a linear relationship between years of exposure and the amounts of DPC and SCE. The authors conclude that the data indicate a possible mechanism of carcinogenicity of formaldehyde, and that formaldehyde is mutagenic to humans. These results support the use of DPCs as a biomarker of occupational exposure to formaldehyde and to detect high-risk populations for secondary prevention.

Biological monitoring of exposure to cadmium, a human carcinogen, as a result of active and passive smoking.

Cadmium (Cd), a known human carcinogen, is one of the components of tobacco and also has many industrial uses. Smoking Cd-contaminated cigarettes at work may cause an increase in blood levels and toxicity of Cd. For a population of nonexposed workers, we compared blood Cd and urine cotinine (Cot) levels as biological markers of exposure to cigarette smoke of active smokers (AS) and passive smokers (PS) with those of unexposed nonsmokers (UNS) in 158 workers. The mean Cd in AS (0.097 microgram%; ie, 0.097 microgram/100 mL whole blood) was significantly higher than in UNS (0.085 microgram%), and was very close to the mean Cd levels in PS (0.093 microgram%). Mean Cd levels in exposed past smokers (0.105 microgram% was higher than in nonexposed past smokers (P < 0.05) and in AS. The mean Cot level was significantly higher in AS than in PS or in UNS. Increased smoking was associated directly with increased blood Cd and urine Cot. Our results supported and proved quantitatively that exposure to cigarette smoke is harmful to both AS and PS, as we show that in both cases there is an increase in blood Cd. According to our results, exposure to cigarette smoke via active and passive smoking increases blood Cd by an average of 0.01 micrograms% over the background (UNS). We conclude that exposure to cigarette smoke is a confounder to be taken into account when carrying out epidemiological studies and surveillance programs on workers exposed to Cd at work.

[Occupation and bladder cancer].

The proportion of all cancers attributed to occupational environment has been estimated at only 4% (range 2-8%), although 20% of bladder carcinoma is occupationally related. In Israel, 7 substances have been established as bladder carcinogens and another 2 are suspected. The linkage between bladder cancer and occupation was examined according to occupational history and work-place exposure; smoking habits were also noted. The study population consisted of 1230 patients diagnosed as suffering from bladder cancer in 1988-1993 in 5 central hospitals; 80% were men, mean age 68.9 +/- 10.8 years. Only 41% of the files (mean 45%, range 13-69%) had information about last job, but no information on exposure. The information in 226 files out of 500 (45%) about previous occupations indicated potential association with bladder cancer in 68%. These occupational fields were: medicine (doctors, nurses), building and agriculture, and comprised 27.6% of all jobs reported. Other occupations connected with bladder cancer reported with lesser frequency were in the paint, rubber, textile and leather industries. There was information about smoking, a known carcinogen for bladder cancer, in only 59% of the files. Our findings indicate that the overall situation in Israel is similar to that in other countries. There is a connection between bladder cancer and exposure to carcinogens at work, but the medical files were not a good source of information regarding the precise extent of this problem. Recording occupational history is important for proper medical surveillance of high risk populations, for early detection of bladder cancer, and for prevention of further exposure.

DNA--protein crosslinks, a biomarker of exposure to formaldehyde--in vitro and in vivo studies.

Formaldehyde (FA) is a widely produced industrial chemical. Sufficient evidence exists to consider FA as an animal carcinogen. In humans the evidence is not conclusive. DNA-protein crosslinks (DPC) may be one of the early lesions in the carcinogenesis process in cells following exposures to carcinogens. It has been shown in in vitro tests that FA can form DPC. We examined the amount of DPC formation in human white blood cells exposed to FA in vitro and in white blood cells taken from 12 workers exposed to FA and eight controls. We found a significant difference (P = 0.03) in the amount of DPC among exposed (mean +/- SD 28 +/- 5%, minimum 21%, maximum 38%) than among the unexposed controls (mean +/- SD 22 +/- 6%, minimum 16%, maximum 32%). Of the 12 exposed workers, four (33%) showed crosslink values above the upper range of controls. We also found a linear relationship between years of exposure and the amount of DPC. We conclude that our data indicate a possible mechanism of FA carcinogenicity in humans and that DPC can be used as a method for biological monitoring of exposure to FA.

The correlation between blood and urine level of cadmium and nasal and paranasal sinuses disorders.

Over exposure to cadmium may produce numerous adverse health effects, including changes in the nasal mucosa. Cadmium levels were measured in blood and urine samples taken from 106 workers who were exposed to high levels of cadmium and nickel in a cadmium nickel battery plant. Pathological results were observed in 46% and 51% of the blood and urine samples respectively. A positive association was found between clinical nasal complaints and pathological levels of cadmium in blood (P = 0.006) and urine (P = 0.045) samples. All the workers underwent sinus X-rays and 63% of them were abnormal. No correlation was found between pathological sinus X-rays and pathological cadmium level in blood and urine samples. A positive correlation was found between clinical nasal complaints and abnormal sinus X-rays. The prevalence of sinus X-ray abnormalities in an asymptomatic general population is 33% as compared to 63% in our study. This difference is highly significant statistically (P < 0.0001). Our result shows a possible harmful effect of cadmium on the paranasal sinuses.

Occupational cancer in Israel: an overview.

Occupational cancer is a result of exposure to carcinogens in the workplace. The critical interaction during the initiation stage of the carcinogenesis process occurs between the ultimate form of a carcinogen and the DNA, resulting in the formation of a DNA adduct or several types of gross structural alterations. Several methods have been developed by which carcinogens can be detected. These methods can be utilized for ambient monitoring of exposure and health surveillance. "Molecular epidemiology" is the combination of epidemiologic and laboratory studies, i.e., monitoring exposure by measuring the DNA adduct. Early detection of occupational cancer is difficult, due largely to the latent period which can be up to 20 years or more. For this reason it is important to develop and improve techniques for early detection of premalignant changes. Israel has numerous workers who are exposed to carcinogens, but has no special legislation concerning the use of carcinogenic substances in the workplace. However, an interministerial committee has published, and is continuing to work on, exposure and safety regulations. Medical surveillance and prevention as well as legislation are necessary to reduce morbidity and mortality from occupational cancer.

Cytogenetic changes in ethylene oxide-exposed workers: a challenge to occupational medicine.

Ethylene oxide is a colorless gas that can cause neoplastic disease (leukemia, stomach cancer) in animals and humans. Its mutagenic potential is expressed by chromosome aberrations and sister chromatid exchange, as has been shown in numerous studies of groups exposed to ethylene oxide. The results of our pilot study on the effects of exposure to high levels of ethylene oxide show chromosome breakage in exposed individuals at twice the frequency of the normal population. Although these are preliminary findings, they justify urgent, specific protection from further exposure.

[Passive smoking: clinical aspects and workers' awareness].

Tobacco smoke contains a wide range of toxic vapors and particles which when inhaled are injurious both to the smoker himself (active smoking) and to those around him (passive smoking). It is extremely difficult to define precisely the harmful effects of passive smoking on the individual's health because of problems in quantifying the extent of exposure. A number of epidemiological studies indicate that exposure to passive smoking in public places is circumstantially, but marginally, linked to cardiovascular morbidity and mortality, as well as to pulmonary morbidity. both benign and malignant. Many clinical conditions are further aggravated by exposure to a combination of tobacco smoke and other industrial materials, including cadmium, and radon daughters. Passive smoking during pregnancy constitutes a health hazard for both mother and fetus. Exposure to passive smoking during childhood may predispose to benign and malignant pulmonary morbidity in adulthood. For many the workplace is the main site of exposure. In a pilot study during the past year on 1197 white and blue-collar workers, we found that the proportion of nonsmokers exposed to tobacco smoke at work is very high, almost 80%, and that workers are bothered by it. 2/3 are aware of the serious adverse health effects of tobacco smoke. 98% of the passive smokers and 75% of the active smokers considered legislation to limit smoking in public places justified.

The consequences of passive smoking: an overview.

Tobacco smoke contains a wide range of toxic vapors and particles that when inhaled are injurious to the smoker himself (active smoking) and to those around him (passive smoking). It is extremely difficult to define precisely the harmful effects of passive smoking on the individual's health because of the problems involved in quantifying the extent of exposure. A number of epidemiological studies indicate that exposure to passive smoking in public places is circumstantially but marginally linked to cardiovascular morbidity and mortality, as well as to benign and malignant pulmonary morbidity. There is an increased risk of cardiovascular and lung diseases among people living with spouses who smoke due to the exposure to tobacco smoke in the home. Passive smoking during pregnancy constitutes a health hazard for mother and fetus alike. Exposure to passive smoking during childhood may predispose the individual to benign and malignant pulmonary morbidity in both childhood and adulthood. For many people the worksite comprises the main exposure source. Many clinical conditions are further aggravated by exposure to a combination of tobacco smoke and industrial chemicals, mineral dust, or other carcinogens (asbestos, cadmium, radon daughters). Tobacco smoke exposure and the resultant morbidity can be reduced by regulations and legislation prohibiting smoking in public places and worksites.

Active specific immunotherapy of renal cell carcinoma patients: a prospective randomized study of hormono-immuno-versus hormonotherapy. Preliminary report of immunological and clinical aspects.

Early results of a prospective, randomized trial of active, specific immunotherapy adjunctive to nephrectomy in all stages of RCC are presented. Forty-three patients with median followup of 30 m, who were randomly allocated to either immuno-hormonotherapy arm (IMT), or hormonotherapy alone (HT), are evaluated in terms of progression-free interval (PFI) and overall survival by life table method. Immunotherapy consisted of autologous irradiated tumor cells (AITC), admixed with bacillus Calmette-Guérin (Glaxo) administered by the intradermal and endolymphatic route. Clinical results of this study show only a trend for advantage of the experimental (IMT) arm over the control (HT) arm, this trend did not reach statistical significance level: prolongation of disease free period in stages I-III with localized disease (p less than 0.1) and prolongation of survival in patients with metastatic disease (p less than 0.07). A correlation was established between induction of cutaneous delayed hypersensitivity (DTH) to AITC and prolonged PFI and survival: patients with positive DTH had a significantly better course of disease than those who could not be converted to positivity after repeated immunizations. Positive in vitro leukocyte migration inhibition against autologous tumor preparations correlates well with positive in vivo cutaneous DTH. Some immunological aspects of active immunization with autologous tumor cells are discussed.

Serial circulating immune complex values and development of metastatic disease in breast cancer and malignant melanoma patients.

A polyethylene glycol precipitation technique was used to determine the levels of circulating immune complexes (CIC) in breast cancer and melanoma patients. All patients in the study had undergone surgery and were free of distant metastatic disease. CIC were measured at two to four time intervals, of 3 to 6 months each, over an average follow-up period of 13.5 months (range 7-20 months). In both groups of patients, metastatic disease developed with a higher frequency in patients who had undetectable CIC levels throughout the follow-up period or had become negative at the time metastases were discovered.

Glitches and pinned vorticity in the Crab pulsar.

We suggest that the glitch behavior observed in the Crab pulsar is associated with vorticity jumps induced by a starquake or a comparable external fluctuation in the weakly pinned vortex region expected in the crust of a young neutron star, and that the differences in the glitch behavior of the Crab, Vela, and older pulsars may be explained on evolutionary grounds.