Biomedical subjects

J Ribak

Publications and source records attributed to J Ribak.

At least 55 records · Page 3Linked to original sources

PubMed1997

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.

Journal Article↗

PubMed1997

The Need for Consistent Criteria for Impairment and Disability.

Medical committees that are responsible for pension funds (FMCs) rarely agree with decisions taken by occupational physicians to displace workers from their workplaces and to certify their eligibility for retirement on medical grounds. The major reason for this substantial disagreement, as demonstrated in this article, is a difference between the definition of disability used by the FMCs and that used by the employers or the occupational physicians. The dispute is usually about the evaluation of the worker's ability to function well in an alternative suitable job or with some modification in the customary job. It is also obvious that work options that existed in the past and were offered to disabled workers are diminishing nowadays due to technological and economic advances. The meaning of this disagreement to employers is that they can find their enterprises stuck with disabled workers who are unable to continue their jobs but are not entitled to pensions from the fund because they are considered suitable to cope with another theoretical job. The authors conclude with several approaches to avoiding certain dilemmas concerning the medical aspects associated with the displacement of disabled workers.

Journal Article↗

PubMed1997

Exercise blood pressure changes between seasons.

BACKGROUND: Blood pressure (casual and daytime) is higher in winter than it is in summer, and this factor might be partly responsible for the higher cardiovascular mortality in winter. OBJECTIVE: To determine in a prospective study whether there is also a seasonal variation in exercise blood pressure. METHODS: We evaluated the pretest, exercise (five-step treadmill test) and recovery values of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate of 94 healthy men, aged 20-65 years, during the summer and winter. RESULTS: SBP and DBP values were higher in winter than they were in summer during the resting period immediately before exercise (P = 0.003 and P = 0.07, respectively), and during recovery (both P < 0.0001). Exercise SBP and heart rate values were similar in the two seasons, although exercise DBP was higher in winter than it was in summer (P < 0.0001). The increase in DBP from pretest to stage 3 was 6.5 mmHg in summer and 10.4 mmHg in winter (P = 0.002). After we had controlled for possible confounders, the increase in DBP during exercise was found to be independently associated with season of the year and resting DBP. CONCLUSIONS: Exercise DBP varies according to season whereas exercise SBP does not. Our results suggest that, since measures of the response of blood pressure to exercise testing are frequently used in blood pressure and hypertension research as well as in clinical practice, the seasonal influences should be taken into account.

Journal Article↗

PubMed1997

Seasonal differences in blood cell parameters and the association with cigarette smoking.

Seasonal changes in red cell parameters need to be defined in order to properly interpret laboratory results. In this study blood counts were obtained prospectively in 104 healthy men (84 non-smokers and 20 smokers) aged 28-63 years during the summer and winter months. Seasonal changes in plasma volume were also calculated. In healthy non-smokers, their haemoglobin concentration and haematocrit ratio were lower in summer than in winter with a concomitant 5.5% increase in plasma volume. In smokers, there was no change in plasma volume, but haematocrit levels increased in summer. We conclude that both smoking status and seasonal variation should be taken into account in the evaluation of blood count results. Further studies are warranted to determine if our results can be extrapolated to subjects of both sexes and of various ages exposed to different climatic conditions.

Adult↗

PubMed1996

[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.

Aged↗

PubMed1996

[Guidelines for treating low back pain in primary care. The Israeli Low Back Pain Guideline Group].

Low back pain (LBP) is a common problem in primary care, the successful management of which poses special challenges for patients and practitioners alike. It has been estimated that all adults will suffer LBP sometime during their lifetimes. It is one of the most frequent reasons for visiting a primary care physician, yet practitioners often find it difficult and frustrating to treat. This medical protocol is concerned with the diagnosis, treatment, and follow-up of low back pain in adults. It was developed for community-based, primary care physicians (general practitioners, family physicians, and internists) to serve as a general outline, to be adjusted in accord with the individual's circumstances. The protocol provides a "Ten Commandments" for the care of LBP, outlines the background of the problem, presents an overall algorithm and deals with issues of diagnosis, imaging, and treatment. In general, LBP in primary care is conceived of as a benign ailment, and emphasis is placed on reducing pain, resuming functioning and returning to work. The main task of the physician is to distinguish the less than 10% of cases with serious, specific causes of LBP from the more than 90% with nonspecific etiologies. In the great majority of patients, imaging studies such as X-ray, CT, MRI, and bone scan, and also EEG are unnecessary.

Family Practice↗

PubMed1996

Body mass index is associated with differential seasonal change in ambulatory blood pressure levels.

Seasonal changes in blood pressure may be partially explained in thermoregulatory terms. We hypothesized that the seasonal variation in blood pressure is related to body mass index, due to the increased thermoregulatory requirements of leaner individuals. Ambulatory systolic and diastolic blood pressure were monitored once each in summer and winter in 101 healthy normotensive men aged 28 to 63 years. Environmental conditions and body mass index were measured. The population was divided according to quartiles of body mass index. The percentage of subjects with systolic blood pressure increases of more than 10 mm Hg from summer to winter was highest among subjects in the lowest body mass index category, and lowest among those in the highest body mass index category (35% and 8%, respectively, P < .0001). After adjusting for possible confounders, the change in mean systolic blood pressure from summer to winter was inversely associated with body mass index (beta = -0.26, P = .0149). There was no association between diastolic blood pressure change and body mass index. The increase in systolic blood pressure from summer to winter is inversely and independently associated with body mass index. Hypertension research and epidemiological blood pressure studies should take into account the interaction between season, body mass index, and blood pressure. It may also be important to assess hypertension and response to antihypertensive treatment in relation to season, particularly in lean hypertensives.

Adult↗

PubMed1996

Usefulness of the protection motivation theory in explaining hearing protection device use among male industrial workers.

The present study examined the usefulness of personal variables: noise annoyance, and components of the protection motivation theory (R. W. Rogers, 1983) along with social-organizational factors in explaining hearing protection device (HPD) use among Israeli manufacturing workers. Participants were 281 men exposed to harmful noise levels for which routine HPD use is required by regulation. In practice, 3 HPD user groups were identified: nonusers (n = 38), occasional users (n = 125), and regular users (n = 118). HPD use was objectively verified. HPD use was primarily related to the personal variables but not to management pressure, coworker pressure, or family support. The most powerful predictors of HPD use were perceived self-efficacy (for long-term HPD use), perceived susceptibility (to hearing loss), and noise annoyance, together explaining 48% of the outcome variance. These findings have implications for interventions aimed at motivating workers to use HPDs regularly.

Adolescent↗

PubMed1996

Hostility and hearing protection behavior: the mediating role of personal beliefs and low frustration tolerance.

The authors examined whether hostility would negatively be associated with occupational health behavior, namely, the use of hearing protection devices (HPDs). Also examined as possible mediators were the protection motivation theory (PMT) components and low frustration tolerance (LFT). Participants were 226 male industrial workers, all exposed to potentially hearing-damaging noise. Hostility was negatively related to HPD use. It moderately correlated with the PMT components: negatively with perceived susceptibility, severity, effectiveness, and self-efficacy and positively with perceived barriers. Hostility correlated highly with LFT. Regression analyses confirmed the mediating role of perceived barriers, low self-efficacy, and LFT in the negative relationship between hostility and the use of HPDs. Thus, intrapsychic characteristics of hostile people may be significant for hearing protection behavior.

Adolescent↗

PubMed1996

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.

Biomarkers↗

PubMed1996

A graduate course in work site health promotion for occupational health practitioners.

This paper describes the rationale, teaching strategies, outcomes, and a 6-month follow-up of an academic course in work site health promotion, in which 35 occupational health practitioners participated. The one-semester course was part of the Masters in Science program in occupational health at the Tel-Aviv University Medical School. The primary goals of the study were to teach the theoretical bases of work site health promotion and their application to specific health needs, and to train better role models for employees. The primary teaching strategies were: (1) facilitation of experiential learning, by encouraging students to undergo health screening and then engage in a personal health promotion plan; (2) use of health promotion experts as guest teachers; and (3) an increase in formal knowledge through formal lectures and background reading. At the time of follow-up, most of the students were still adhering to their plans and maintaining much of their health promotion achievements. Additional outcomes included increased awareness of health risks and health promotion issues, and positions as role models in the private and professional domains. The primary barrier to adherence was low frustration tolerance, which can be regarded as the major challenge to health promotion programs and courses. It is suggested that the course format is an effective means of educating health promoters.

Adult↗

PubMed1996

Fatigue among Israeli industrial employees.

We examined the prevalence of fatigue and its association with occupational conditions and health-related habits in 3785 industrial employees of six industrial sectors to define modifiable factors. The factors examined included complaints of fatigue during and after work, an ergonomic evaluation of employees' workstations, demographic characteristics, and health-related habits. Eighteen percent of the subjects complained of severe fatigue frequently or very frequently. We were able to identify two major modifiable variables that were independently associated with the presence of fatigue. Logistic regression showed that those workers who did not participate in physical activity at least once a week had a 1.7-fold increase in prevalence of severe fatigue (95% confidence interval = 1.3 to 2.3, P < 0.001). The other major modifiable factor was temperature control, with those workers who worked at non-temperature-controlled workstations having a 50% increase in the prevalence of fatigue (odds ratio = 1.5, 95% CI = 1.1 to 2.1; P = 0.01). Accidents were significantly more frequent in those workers with fatigue. Further studies should focus on intervention programs to modify the factors identified by this study.

Adult↗

PubMed1996

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.

Biomarkers↗

PubMed1996

Industrial accidents are related to relative body weight: the Israeli CORDIS study.

OBJECTIVES: The accident rate might be influenced by intrinsic characteristics of the workers, by risks inherent in the work environment, or a combination of these factors. As increased weight may be associated with sleep disturbances and fatigue, a high body mass index (BMI) might be an independent risk factor for accidents in industrial workers. METHODS: 3801 men were examined and followed up for two years for the occurrence of accidents. The objective environmental conditions were recorded and translated into a single score of ergonomic stress levels. Height and weight were recorded, as were possible confounding factors including measures of fatigue, type A personality, total night time sleep, job satisfaction, somatic complaints, smoking, and education levels. RESULTS: Both BMI and ergonomic stress levels independently predicted involvement in accidents (two or more) with those in the highest BMI quartile who worked in an environment with high ergonomic stress levels having a 4-6 times increased risk of accidents compared with those in the lowest BMI quartile who worked in an environment with low ergonomic stress levels (95% confidence interval (95% CI) 2.4-9.0, P < 0.001). Although increasing somatic complaints and a low educational level also were predictors of accidents, they did not mediate the effect of the BMI on the accident rate. Increasing age, less smoking, and decreased sleep hours were significantly associated with an increased BMI, but the association of BMI and involvement in accidents also could not be explained by those factors or the other confounders. CONCLUSIONS: BMI independently influences the accident rate. Further studies warranted to confirm these findings and to explore mechanisms supporting biological plausibility.

Accidents, Occupational↗

PubMed1996

Summer-winter variation in 24 h ambulatory blood pressure.

OBJECTIVE: To examine possible seasonal differences in circadian blood pressure patterns and the specific contribution of indoor temperature. METHOD: Twenty-four-hour ambulatory systolic blood pressure (SBP) and diastolic blood pressure (DBP) were monitored once in summer and once in winter in 101 healthy subjects aged 28-63 years. Subjects were interviewed concerning health-related habits, and measurements of environmental and occupational conditions were obtained. RESULTS: After controlling for possible confounders, mean SBP during work was significantly higher in winter than in summer by 3.4 mmHg. Both in winter and in summer, the highest values were recorded during work. The daily SBP circadian amplitude was higher in winter, reflected by higher mean SBP during the day and lower mean SBP at night. All of the daytime DBP measurements were higher in winter than in summer, but at night there were no seasonal differences. The blood pressure showed an independent association with season and with environmental temperature (SBP) beta = 3.98 mmHg and -1.14 mmHg/ degrees C, respectively; DBP beta =4.39 mmHg and -0.58 mmHg/ degrees C, respectively).CONCLUSION: In healthy men, the daily amplitude of ambulatory blood pressure varies physiologically by season with the highest values being obtained during work time in the winter months. If these results can be extrapolated to hypertensives then it might be necessary to tailor drug therapy to these variations. The daily average or clinical measurements may lead to an underestimation of the extent of the seasonal variation in blood pressure. The season of the year must be controlled for in clinical and epidemiological studies comparing blood pressure levels and amplitudes between groups or between baseline and follow-up study.

Journal Article↗

PubMed1996

Preventing burnout: increasing professional self efficacy in primary care nurses in a Balint Group.

Nursing is reported to be a stressful occupation, and chronic stress is often associated with burnout. Many ways of reducing stress have been proposed. Of these, the Balint group method provides a forum in which health professionals can present and attempt to resolve stressful situations with clients, coworkers, or other professionals. Balint groups help health professionals improve coping with psychosocial stressors in a supporting and accepting group atmosphere. This article reports changes in professional self efficacy associated with reduced burnout in a group of 13 nurses working in community based primary care clinics. Results showed significant increases in awareness and ability cognitions after the Balint group and reduced emotional exhaustion and cognitive weariness. The ramifications of these findings are discussed.

Adaptation, Psychological↗

PubMed1996

Disease evaluated on return-to-work examinations: aviation ground personnel compared to other workers.

Aviation ground personnel are subjected to a wide range of chemical and physical exposures that may lead the occupational physician to see a different spectrum of morbidity in the airport compared to other settings. It is essential to determine the most common medical problems in airport ground personnel in order to identify possible work-related conditions and in order to set the priorities for establishing health promotion programs and training occupational physicians. We compiled the diagnoses in 1000 consecutive visits of ground workers to the airport clinic for return-to-work examinations, and compared them to 7000 workers seen in general occupational clinics. The frequencies of the various categories of disease were similar in both type of clinics, except that low back pain was significantly more common in the ground personnel [251 (20.6%) vs. 1176 (15.2%), p < 0.003]. Over 80% of the diseases occurred in 10 diagnostic categories: cancer, fractures, hypertension, ischemic heart disease, knee pain, low back pain, neck pain, operations for various medical conditions, phonal trauma, and pregnancy. We conclude that, except for low back pain, the spectrum of disease seen in the airport clinic is not significantly different from that seen in general occupational medicine clinics. Focusing on the interaction of a limited number of diseases with the work environment will provide the occupational physician with a comprehensive training program, and the emphasis needed for establishing health promotion programs.

Aviation↗

PubMed1996

Improving the professional self-efficacy cognitions of immigrant doctors with Balint groups.

Immigrant doctors have been found to exhibit professional distress, especially if they are retrained to another medical specialty. This study looks at the effects of a long-term Balint group in increasing professional self-efficacy cognitions of immigrant physicians treating drug addicts in a home-based community program in their adopted homeland. Results of the group showed positive significant changes in specific self-efficacy cognitions related to treatment of drug addicts in the community, and an increase in psychosocial self-efficacy from baseline to three other assessment points. The importance of long-term Balint groups with doctors in general and with retraining immigrant doctors in particular is also carefully elucidated.

Community Mental Health Services↗