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Biomedical subjects

K M Conrad

Publications and source records attributed to K M Conrad.

At least 19 recordsLinked to original sources
PubMed2000

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.

Allied Health Personnel↗
PubMed2000

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.

Allied Health Personnel↗
PubMed2000

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.

Back Pain↗
PubMed1999

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.

Adolescent↗
PubMed1998

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.

Adult↗
PubMed1997

The type I angiotensin II receptor couples to Stat1 and Stat3 activation through Jak2 kinase in neonatal rat cardiac myocytes.

The octapeptide, angiotensin II, has a modulatory role on cardiac cellular growth associated with hypertension and in compensatory remodeling following myocardial infarction. The molecular signal transduction pathways that participate in these and other cellular actions in response to angiotensin II are presently being elucidated. The signal transducers and activators of transcription (STAT) pathway directly links cytokine and growth factor receptors with transcriptional activity. We provide evidence that the G protein-linked, angiotensin II, AT1-receptor couples to activation of the STAT pathway in neonatal rat cardiac myocytes. Angiotensin II induces primarily sis-inducing factor (SIF) B and to a lesser extent SIF-C and SIF-A. The EC50 of this response was 40 nM and Stat1 and Stat3 proteins were identified as components of the SIF complexes. Stat1 and Stat3 were tyrosine phosphorylated five-fold and three-fold, respectively, over control levels following angiotensin II treatment of cardiac myocytes. Phosphorylation of Stat1 and Stat3 proteins was rapid (5 min) and sustained (60 min). Jak2 was also tyrosine phosphorylated eight-fold by angiotensin II treatment, and phosphorylated Stat1 and Stat3 proteins co-immunoprecipitated with activated Jak2 kinase. Selective inhibition of Jak2 kinase with AG-490 blocked formation of angiotensin II induced SIF complexes, suggesting that Jak2 kinase is required for cardiomyocyte SIF induction. In addition, Jak2, Stat1 and Stat3 proteins co-immunoprecipitated with the AT1-receptor. These are the first data to demonstrate coupling of a G-protein coupled receptor, AT1, to the JAK-STAT pathway in primary cultured cardiac myocytes and suggest that this pathway may be involved in transcriptional regulation by angiotensin II.

Angiotensin II↗
PubMed1997

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.

Adult↗
PubMed1997

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.

Adult↗
PubMed1996

Endothelin stimulates sis-inducing factor-like DNA binding activity in CHO-K1 cells expressing ETA receptors.

ET-1, a member of the family of peptides known as endothelins, binds to a G-protein-coupled receptor, ET(A), and stimulates a variety of cellular responses, including contraction, growth, and mitogenesis. ET-1 stimulation of a chinese hamster ovary cell line stably transfected with the ET(A) receptor (CHO/ET(A)) induced formation of SIF (sis-inducing factor), a key component of the STAT (Signal Transducers and Activators of Transcription) pathway, in a concentration-dependent manner. SIF induction was blocked by a specific inhibitor of ET(A), BQ610, and by genistein, a tyrosine kinase inhibitor. This report demonstrates that ET-1 stimulates the STAT pathway of signal transduction through a G-protein-coupled receptor, ET(A), in this stably transfected cell line.

Animals↗
PubMed1996

The worksite environment as a cue to smoking reduction.

With a modified version of the Health Belief Model as the conceptual framework, the hypothesis that exposure to a worksite health-promoting environment acted as a cue to smoking reduction among 310 smokers was tested with a quasi-experimental design. Using path analysis (LISREL), the total effects on posttest smoking were decomposed. Results showed exposure to the health-promoting environment had statistically significant direct and indirect effects on posttest smoking. The indirect effect was through the posttest perceived barriers variable. The LISREL model explained 74% of the variance in smoking reduction and fit the data satisfactorily. The importance of developing the worksite as a health-promoting force is discussed.

Adult↗
PubMed1996

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.

Animals↗
PubMed1996

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.

Exercise Therapy↗
PubMed1995

A role for cAMP in angiotensin II mediated inhibition of cell growth in AT1A receptor-transfected CHO-K1 cells.

G-protein coupled Angiotensin II receptors (AT1A), mediate cellular responses through multiple signal transduction pathways. In AT1A receptor-transfected CHO-K1 cells (T3CHO/AT1A), angiotensin II (AII) stimulated a dose-dependent EC50 = 3.3 nM) increase in cAMP accumulation, which was inhibited by the selective AT1, nonpeptide receptor antagonist EXP3174. Activation of protein kinase C, or increasing intracellular Ca2+ with ATP, the calcium ionophore A23187 or ionomycin failed to stimulate cAMP accumulation. Thus, AII-induced cAMP accumulation was not secondary to activation of a protein kinase C- or ca2+/calmodulin-dependent pathway. Since cAMP has an established role in cellular growth responses, we investigated the effect of the AII-mediated increase in cAMP on cell number and [3H]thymidine incorporation in T3CHOA/AT1A cells. AII (1 microM) significantly inhibited cell number (51% at 96 h) and [3H]thymidine incorporation of 68% at 24 h) compared to vehicle controls. These effects were blocked by EXP3174, confirming that these responses were mediated through the AT1 receptor. Forskolin (10 microM) and the cAMP analog dibutyryl-cAMP (1 mM) also inhibited [3H]thymidine incorporation by 55 and 25% respectively. We extended our investigation on the effect of AII-stimulated increases in cAMP, to determine the role for established growth related signaling events, i.e., mitogen-activated protein kinase activity an tyrosine phosphorylation of cellular proteins. AII-stimulated mitogen-activated protein kinase activity and phosphorylation of the 42 and 44 kD forms. These events were unaffected by forskolin stimulated increases in cAMP, thus the AII-stimulated mitogen-activated protein kinase activity was independent of cAMP in these cells. AII also stimulated tyrosine phosphorylation of a number of cellular proteins in T3CHO/AT1A cells, in particular at 127 kD protein. The phosphorylation of the 127 kD protein was transient, reaching a maximum at 1 min, and returning to basal levels within 10 min. The dephosphorylation of this protein was blocked by a selective inhibitor of cAMP dependent protein kinase A, H89-dihydrochloride and preexposure to forskolin prevented the AII-induced transient tyrosine phosphorylation of the 127 kD protein. These data suggest that cAMP, and therefore protein kinase A can contribute to AII-mediated growth inhibition by stimulating the dephosphorylation of substrates that are tyrosine phosphorylated in response to AII.

Angiotensin II↗
PubMed1995

Activation of the STAT pathway by angiotensin II in T3CHO/AT1A cells. Cross-talk between angiotensin II and interleukin-6 nuclear signaling.

We recently reported that angiotensin II (AII), acting through the STAT (Signal Transducers and Activators of Transcription) pathway, stimulated a delayed SIF (sis-inducing factor)-like DNA binding activity (maximal at 2-3 h) (Bhat, G.J., Thekkumkara, T.J., Thomas, W.G., Conrad, K.M., and Baker, K.M. (1994) J. Biol. Chem. 269, 31443-31449). Using a cell line transfected with the AT1A receptor (T3CHO/AT1A), we further characterized the AII-induced SIF response and explored the possible reasons for the delay in stimulated SIF activity. In cells transfected with a chloramphenicol acetyltransferase reporter plasmid, under the control of a SIE (sis-inducing element), AII markedly stimulated chloramphenicol acetyltransferase activity. The delayed SIF activation by AII was not due to a requirement for the release of other SIF inducing factors into the medium and contrasts with the rapid (5 min) induction elicited by the cytokine, interleukin-6 (IL-6). Interestingly, both agents stimulated tyrosine phosphorylation of Stat92 and predominantly the formation of SIF complex A. We tested the hypothesis that AII initially activated an inhibitory pathway, which was responsible for delaying the maximal SIF stimulation until 2 h. Pretreatment of cells for 15 min with AII resulted in significant inhibition of the IL-6 induced nuclear SIF response (10 min) and Stat92 tyrosine phosphorylation, which was blocked by EXP3174, an AT1 receptor antagonist. This inhibition was transient with return of the IL-6-induced SIF response at 2 h, suggesting that the delayed maximal activation of SIF by AII occurs following an initial transient inhibitory phase. Pretreatment of cells with phorbol 12-myristate 13-acetate for 15 min, to activate protein kinase C, resulted in inhibition of the IL-6-induced SIF response (10 min). However, down-regulation of protein kinase C activity prevented phorbol 12-myristate 13-acetate, but not AII mediated inhibition of the IL-6-induced SIF response. Although the mechanism is not clear, the results presented in this paper raise the interesting possibility that the activation of SIF/Stat92 by AII is characterized by an initial inhibitory phase, followed by the induction process. The observation that AII and IL-6 utilize similar components of the STAT pathway and that AII can cross-talk with IL-6 signaling through inhibition of IL-6-induced SIF/Stat92, implies a modulatory role for AII in cellular responses to cytokines.

Angiotensin II↗
PubMed1995

Angiotensin II is a potent stimulator of MAP-kinase activity in neonatal rat cardiac fibroblasts.

We have previously shown that angiotensin II (AII) is a mitogen for neonatal rat cardiac fibroblasts. However, the signaling events that lead to fibroblast cell growth in response to AII remain to be elucidated. Mitogen-activated protein (MAP) kinases are cytosolic serine/threonine kinases which have been shown to be activated in quiescent cells by diverse growth stimuli, thereby being linked to growth regulatory pathways. This study was designed to determine whether MAP-kinase activation occurred in response to AII/receptor coupling in neonatal rat cardiac fibroblasts and the role of MAP-kinase activation in the AII-induced proliferation of these cells. Immunoblot analysis of MAP-kinase isoforms revealed predominantly p44 with less p42 MAP-kinase in rat cardiac fibroblasts. Both isoforms were activated upon stimulation of the cells with AII for 5 min or platelet derived growth factor-BB for 10 min. Angiotensin II stimulated MAP-kinase in a dose-dependent fashion with an EC50 of 2.5 nM. Two minutes following stimulation with 1 microM AII MAP-kinase activity increased from 90 +/- 17.9 to 477.5 +/- 75.9 pmol/min/mg protein, P < 0.05, n = 4. A smaller, sustained, secondary increase in MAP-kinase activity from 37.7 +/- 5.3 to 110.9 +/- 15.3 pmol/min/mg protein, P < 0.05, n = 4, was observed in response to AII between 120-150 minutes following receptor occupancy. The responses to AII were markedly attenuated by the AT1 receptor antagonist EXP3174. Stimulation of the cells with carbachol induced the first but not the second phase of MAP-kinase activity and this compound had no effect on cellular growth. The second phase of MAP-kinase activity 2-2.5 h after AII stimulation, paralleled data demonstrating that a 2-3 h receptor occupancy with AII was necessary to induce DNA synthesis and fibroblast proliferation. These results indicate that AII stimulates a biphasic activation of MAP-kinase by the AT1 receptor and that this pathway may participate in the AII induced mitogenic response in cardiac fibroblasts.

Angiotensin II↗
PubMed1995

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.

Exercise Therapy↗