Angiotensin-II-binding sites on hepatocyte nuclei.

Angiotensin-II (Ang II) stimulates gene expression and cell growth in several cell types. Studies that have shown localization of Ang II to nuclei of myocytes and hepatic nuclear Ang II binding suggest that these actions may be mediated by nuclear receptors. We characterized Ang II binding to rat liver nuclei, which were free of plasma membrane based on enzyme analysis and electron microscopy. At 18 C, specific binding of 0.1-0.3 nM [125I]Ang II to nuclei and nuclear envelopes reached equilibrium by 2 h. Unlabeled Ang II inhibited [125I]Ang II binding to nuclei with an IC50 of 1.4 +/- 0.2 nM (+/- SE; n = 6). In half of the nuclear preparations, a lower affinity site (IC50, 50.4 +/- 23.6 nM), which accounted for 7-32% of specific Ang II binding, was detected by Scatchard analysis. Results similar to these were obtained with nuclear envelopes. Other Ang peptides competed for binding in the rank order: Ang III (IC50, 2.1 nM) greater than Ang I (IC50, 33) greater than [Des-Phe8]Ang II (IC50, 362) greater than [Des-Asp1-Des-Arg2]Ang II (IC50, 736). Losartan (DuP 753), an AT1 receptor antagonist, inhibited binding (IC50, 10.9 +/- 0.9 nM), whereas the AT2 receptor antagonist PD123177 did not. The pH optimum for binding to nuclear envelopes was 7, with binding more sensitive to low (5 and 6) than high (8 and 9) pH. Nonhydrolyzable GTP analogs accelerated displacement of bound [125I]Ang II by 10(-5) M Ang II. Differences were noted in pH sensitivity, time course, binding affinity for Ang I, II, and III, and rate of dissociation between nuclei or nuclear envelopes and plasma membrane Ang II binding. These results suggest that nuclear envelopes have a G-protein-coupled Ang II-binding site, which belongs to the AT1 class of Ang II receptors, with properties different from the plasma membrane receptor.

Validity of three lumbar sagittal motion measurement methods: surface inclinometers compared with radiographs.

Three surface methods for measuring lumbar sagittal motion (LSM) were tested for validity using radiographs as the "gold standard" reference. The three methods used were the Pleurimeter V double inclinometer, the carpenter double inclinometer, and the computerized sensor single inclinometer. In this study, 30 volunteers were examined independently by three occupational health professionals. Each volunteer rotated twice through three stations at which LSM was measured by each of the three methods. Radiographs were made during the first rotation. Predictability of the skin marks of T12 and S1 for the corresponding bone measures was acceptable for one examiner, mixed for another, and unacceptable for a third. The intraclass correlation coefficients (ICCs) ranged from 0.81 to 0.99, with half above the acceptable level of 0.90. However, the skin marks and the bone measures showed a linear relationship for all examiners (r > or = 0.89). For flexion and extension, all ICCs between the radiograph and each surface method were far below 0.90, indicating poor validity for each surface method. We concluded that skin placement of T12 and S1 has a linear relationship to bony landmarks, and that each of the tested surface methods does not validly measure LSM.

Reliability of three lumbar sagittal motion measurement methods: surface inclinometers.

Three surface methods for measuring lumbar sagittal motion (LSM) were tested for reliability. The three methods used were the Pleurimeter V double inclinometer, the carpenter double inclinometer, and the computerized single sensor inclinometer. In this study, 30 volunteers were examined independently by three occupational health professionals. Each volunteer rotated twice through three stations at which LSM was measured by each of the three methods. The intra- and interexaminer reliabilities in identifying the skin levels of T12 and S1 were acceptable, having intraclass correlation coefficients (ICC) greater than or equal to 0.75. With a single exception, all ICC values for the intraexaminer reliability of LSM measurements fell below 0.90 (a clinically desirable level). The interexaminer reliability was poor, with all ICC values below 0.75. The largest source of measurement error was attributable to the examiner and its associated factors. We concluded that the intra- and interexaminer reliabilities varied greatly, limiting the clinical usefulness of the three surface methods.

Threats to internal validity in worksite health promotion program research: common problems and possible solutions.

Reviews of the research on worksite health promotion programs reveal that most studies are limited in their ability to draw clear inferences about program effects because the studies employed flawed research designs and/or analyses. Conclusions are often drawn about program effectiveness with little consideration given to alternative explanations for the findings. In an effort to promote improved research, this article uses the Cook and Campbell delineation of threats to valid causal inference to illustrate how the threats can operate in worksite health promotion program research as well as how they can be examined and controlled. Researchers, even those attempting to conduct true experiments, must consider the existence of all plausible threats to validity and control or rule them out before valid causal inferences can be drawn. The theoretical and design issues involved in worksite health promotion program research are presented, followed by a discussion of threats to internal validity.

Do blue-collar workers perceive the worksite health climate differently than white-collar workers?

A mail survey was distributed to a random sample of 497 both blue- and white-collar workers employed at a large manufacturing company to measure dimensions of worksite health climate: organizational and interpersonal support, and health norms. Statistically significant differences were observed for nearly all aspects of the dimensions with white-collar workers having more positive perceptions than blue-collar workers. The study suggests that future research explore how these perceptions may be enhanced and what role they may play in promoting worker health.

Relationship of eggshell ultrastructure and shell strength to the soundness of shell eggs.

Factors affecting the soundness of shell eggs are of primary concern to egg processors due to substantial financial losses from cracked and leaker eggs. Ultrastructural analyses were used to examine the palisade layer width and mammillary knob layer thickness of sound, cracked, and leaker eggshells. Subjective observations were also made. There was no significant difference (P > 0.05) in the width of the palisade layer or the mammillary knob layer among sound, cracked, and leaker eggshells. The eggshell strengths of sound, cracked, and leaker eggs were evaluated using puncture force and shell thickness measurements. Sound eggshells were found to have a significantly (P < 0.05) higher mean puncture force (35.3 N) than cracked (30.4 N) and leaker (28.4 N) eggshells. The mean puncture force values for cracked and leaker eggshells were not significantly different from each other (P > 0.05). Regression and correlation analyses indicated a significant correlation (P < 0.01; r = 0.61) between palisade layer width and puncture force. The mean shell thickness values for cracked (0.36 mm) and leaker (0.35 mm) eggs were significantly lower (P < 0.05) than those of sound eggs (0.38 mm), although cracked and leaker eggshell thickness did not differ significantly (P > 0.05). The correlation coefficient between puncture force and shell thickness was significant (P < 0.01; r = 0.56), indicating a possible relationship.

Postural analysis of paramedics simulating frequently performed strenuous work tasks.

Paramedics who perform emergency rescue functions are highly susceptible to musculoskeletal injuries. Through an interview and survey process firefighters, many of whom are cross-trained paramedics in a consortium of 14 suburban fire departments, identified and rated tasks that were perceived to be both strenuous and frequently performed. The objective of the current study was to describe the working postures and the forces applied as firefighter/paramedics (FF/Ps) simulated specific roles within the following tasks identified by the survey: (1) transferring a patient from a bed to a stretcher using bedsheets, (2) transferring a patient from the ambulance stretcher to a hospital gurney, (3) carrying a victim down a set of stairs and around a landing using a stairchair, (4) carrying a victim down a set of stairs and around a landing using a backboard, and (5) carrying a victim down a set of stairs using a stretcher. Ten two-person teams of FF/Ps participated and were videotaped to obtain postural data for the upper and lower extremities as they performed each role in the simulated two-person tasks. Trunk postures were obtained using lumbar motion monitors. Static hand forces were estimated using a hand-held dynamometer at the most physically demanding points for each role within each task. The postural and force data were averaged across subjects performing identical roles to quantify the postures assumed by the FF/Ps at the most strenuous moments during task performance. Based on these analyses we concluded that: (1) when transferring victims from a bed to a stretcher the FF/P on the bed was able to maintain an upright and more stable posture by standing as opposed to kneeling, (2) an interface board should be used to reduce the frictional forces when transferring victims from a bed to a stretcher or from a stretcher to a gurney, thereby reducing the need to lift the victim with flexed torsos and/or shoulders, and (3) equipment and training that encourages the FF/P in the leader role to walk facing forward during victim transport, especially when descending stairs, potentially results in safer transit.

Biomechanical analyses of paramedics simulating frequently performed strenuous work tasks.

Firefighters performing emergency rescue functions are at an elevated risk of musculoskeletal injuries. The objective of the current study was to analyze the biomechanical stresses placed on the body based on simulations of the following strenuous and frequently performed emergency rescue tasks: (1) transferring a patient from a bed to a stretcher using bedsheets, (2) transferring a patient from the ambulance stretcher to a hospital gurney, (3) carrying a victim down a set of stairs and through a landing using a stairchair, (4) carrying a victim down a set of stairs and through a landing using a backboard, and (5) carrying a victim down a straight set of stairs using a stretcher. Postural data were analyzed using the University of Michigan's Three-Dimensional Static Strength Prediction Program and the relative risk of low back disorder (LBD) was quantified using the trunk motion model published by Marras et al. (1993, spine 18, 617-628). Peak compression values and the probabilities from the Marras et al. (1993) model indicated that the most hazardous tasks performed as part of this simulation included pulling a victim from a bed to a stretcher, the initial descent of a set of stairs when using the stretcher, and lifting a victim on a backboard from the floor. Overall, the two models were well correlated in their assessment of the task components modelled (r = 0.78). These data indicate where engineering changes to equipment regularly used by emergency rescue personnel would have the greatest impact in reducing the risk of musculoskeletal injury.

Adherence to worksite exercise programs: an integrative review of recent research.

1. Improving worker physical fitness through worksite exercise programs offers many benefits to the employee and the employer. Unfortunately, a small percentage of workers who begin an exercise program adhere to it. 2. It is essential to design program strategies to promote exercise adherence among persons who do not currently exercise at levels that achieve health benefits. 3. The results of this review of worksite research suggest a number of strategies that were successful in increasing at least short term exercise adherence. 4. Carefully controlled studies are needed to identify specific worksite exercise interventions or combination of interventions that maximize the initiation of exercise as well as short and long term adherence. A combination of strategies improves exercise adherence for at least 6 months, but more research is needed to determine long term maintenance of an exercise program.

Back injury prevention interventions in the workplace: an integrative review.

The purpose of this integrative review is to describe the state of knowledge about the effect of worksite back injury prevention programs on selected study outcomes. Fifteen experimental and quasi-experimental studies published between 1987 and 1994 were identified through a comprehensive literature search. The research studies were reviewed and analyzed using a data collection abstracting tool. Four types of back injury prevention intervention programs were identified: back belts, back schools, exercise/flexibility training, and educational classes. Positive program outcomes were reported for all four program types; however, the back school and the exercise/flexibility training programs were studied more frequently and demonstrated a greater proportion of positive results than the other two program types. Conclusions should be viewed cautiously due to the small number of studies reviewed and their methodological limitations. Implications for occupational health nursing practice and future research related to worksite back injury prevention are offered.

Occupational hazard exposure and at risk drinking.

This study examined associations between workers' reported exposure to occupational hazards and at risk drinking. A sample of 15,907 working adults was drawn from the 1985 National Health Interview Survey (NHIS) (weighted sample represented 85,395,000 workers). This was the only year the NHIS included questions on both occupational hazard exposure and at risk drinking. Occupational hazard exposures included chemical/biological substances, physical hazards, injury risk, and mental stress. At risk drinking was defined as binge drinking and drinking and driving. Prevalence adjusted odds ratios were estimated. Sixty percent of workers reported exposure to one or more occupational hazards with considerable variation among and within occupations. In all, 31% reported binge drinking and 15% drove after drinking too much. In a multivariate analysis that controlled for background characteristics, workers who reported occupational hazard exposures were 1.2 to 1.4 times more likely to engage in binge drinking than workers without exposures. Similar results were found for drinking/driving. All multivariate results were statistically significant. Findings suggest workers who report occupational hazard exposures are at greater risk of both binge drinking and drinking/driving. Occupational and environmental health nurses can lead workplace initiatives to reduce occupational hazard exposure and, simultaneously, invest in health promotion efforts to curb at risk drinking among workers.

Factors associated with male workers' engagement in physical activity: white collar vs. blue collar workers.

The purpose of this study was to identify factors associated with male workers' participation in different kinds of physical activity, noting differences between white collar and blue collar workers. This study examined the variables, perceived health status, self efficacy, perceived barriers, age, education, income, and job category (Pender, 1987) for their association with physical activity. Self efficacy and perceived health status were the cognitive-perceptual factors that predicted physical activity. Job category (e.g., blue collar vs. white collar) was found to be a highly significant predictor of physical activity. Comparing physical job requirements with the individual worker capacity can suggest to the occupational health nurse physical fitness programs that are most appropriate for individual workers.

A case management tool for occupational health nurses: development, testing, and application.

1. Case management is a process of coordinating an individual client's health care services to achieve optimal, quality care delivered in a cost effective manner. The case manager establishes a provider network, recommends treatment plans that assure quality and efficacy while controlling costs, monitors outcomes, and maintains a strong communication link among all the parties. 2. Through development of audit tools such as the one presented in this article, occupational health nurses can document case management activities and provide employers with measurable outcomes. 3. The Case Management Activity Checklist was tested using data from 61 firefighters' musculoskeletal injury cases. 4. The activities on the checklist are a step by step process: case identification/case disposition; assessment; return to work plan; resource identification; collaborative communication; and evaluation.

Noise induced hearing loss among male airport workers in Korea.

The purposes of this study of airport workers were to a) determine the prevalence and symptoms of hearing loss, and b) identify compliance in using hearing protective devices (HPDs) and its relationship with hearing loss. This cross sectional epidemiological study was conducted with 255 noise exposed and 195 non-noise exposed, full time, male workers at a large metropolitan airport in Seoul, Korea. The three measures used were the self administered Occupational Hearing Questionnaire (OHQ), an audiological assessment, and a record review of baseline hearing and noise levels of locations in which the employee worked. The results showed a significant difference in prevalence of hearing loss (more than 25dB) between the noise and the non-noise exposed groups (p < .05). About 60.8% of noise exposed workers reported continuous use of the HPDs. The continuous HPD users had significantly lower rates of hearing loss than the occasional users or non-users. The major symptom for workers with low frequency hearing loss was trouble in communication, whereas tinnitus and fullness in the ear were the most common symptoms for the workers with high frequency hearing loss. The airport workers exposed to excessive noise had a great deal of high frequency hearing loss. The degree of hearing loss present reinforces the need for aggressive hearing conservation programs among airport workers exposed to noise.

Effect of worksite health promotion programs on employee absenteeism. A comparative analysis.

Employee absenteeism is an important economic variable that needs to be examined by occupational health nurses when evaluating worksite health promotion programs. Two of the three Blue Cross and Blue Shield Plan studies suggested that their programs acted to contain absenteeism among program participants. The worksite programs that met with success tended to be comprehensive and to have strong management support. Strengths of the three studies included the use of comparison groups and pretest measures of absenteeism in the analyses. Limitations included selection bias, subject dropout over time, limited monitoring of the program process, and the use of an analysis method that did not consider the statistical characteristics of the absenteeism variable.

Initiating an ergonomic analysis. A process for jobs with highly variable tasks.

Occupational health nurses play a vital role in addressing ergonomic problems in the workplace. Describing and documenting exposure to ergonomic risk factors is a relatively straightforward process in jobs in which the work is repetitive. In other types of work, the analysis becomes much more challenging because tasks may be repeated infrequently, or at irregular time intervals, or under different environmental and temporal conditions, thereby making it difficult to observe a "representative" sample of the work performed. This article describes a process used to identify highly variable job tasks for ergonomic analyses. The identification of tasks for ergonomic analysis was a two step process involving interviews and a survey of firefighters and paramedics from a consortium of 14 suburban fire departments. The interviews were used to generate a list of frequently performed, physically strenuous job tasks and to capture clear descriptions of those tasks and associated roles. The goals of the survey were to confirm the interview findings across the entire target population and to quantify the frequency and degree of strenuousness of each task. In turn, the quantitative results from the survey were used to prioritize job tasks for simulation. Although this process was used to study firefighters and paramedics, the approach is likely to be suitable for many other types of occupations in which the tasks are highly variable in content and irregular in frequency.

Musculoskeletal injuries in the fire service: views from a focus group study.

1. The focus group is a qualitative data collection method involving carefully planned small group discussions designed to obtain perceptions on a defined area of interest. Focus groups can be used by occupational health nurses for gathering ecologically based, in-depth needs assessment information from workers prior to program planning. 2. Occupational health nurses can be guided in their needs assessments by an ecological framework that considers the person, workplace, and situational factors that contribute to occupational health problems. 3. A focus group study of fire chiefs and firefighters used an ecological framework to elicit participants' perceptions of the factors that contribute to musculoskeletal injury and the preventive strategies that would be acceptable to them. Participants shared their insights, motivations, and feelings about the factors, thus suggesting concepts and hypotheses to be explored further. 4. The occupational health nurse needs to consider the differing meanings that management and workers attach to an occupational health problem.

Musculoskeletal injury: ergonomics and physical fitness in firefighters.

As a means of reducing the increasing incidence of musculoskeletal injuries in firefighters, the authors offer a framework for a program that would integrate hazard control and health promotion approaches. Particular focus is placed on the role of ergonomics and physical fitness factors in preventing these injuries.