Invited commentary: tapping the tip of the iceberg.
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Adult↗
Biomedical subjects
Joachim E Fischer
Publications and source records attributed to Joachim E Fischer.
Quantitative diffusion tensor MR imaging of the brain: field strength related variance of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) scalars.
The objectives were to study the "impact" of the magnetic field strength on diffusion tensor imaging (DTI) metrics and also to determine whether magnetic-field-related differences in T2-relaxation times of brain tissue influence DTI measurements. DTI was performed on 12 healthy volunteers at 1.5 and 3.0 Tesla (within 2 h) using identical DTI scan parameters. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured at multiple gray and white matter locations. ADC and FA values were compared and analyzed for statistically significant differences. In addition, DTI measurements were performed at different echo times (TE) for both field strengths. ADC values for gray and white matter were statistically significantly lower at 3.0 Tesla compared with 1.5 Tesla (% change between -1.94% and -9.79%). FA values were statistically significantly higher at 3.0 Tesla compared with 1.5 Tesla (% change between +4.04 and 11.15%). ADC and FA values are not significantly different for TE=91 ms and TE=125 ms. Thus, ADC and FA values vary with the used field strength. Comparative clinical studies using ADC or FA values should consequently compare ADC or FA results with normative ADC or FA values that have been determined for the field strength used.
Analysis of Variance↗
Delayed response and lack of habituation in plasma interleukin-6 to acute mental stress in men.
Acute mental stress induces a significant increase in plasma interleukin (IL)-6 levels as a possible mechanism for how psychological stress might contribute to atherosclerosis. We investigated whether the IL-6 response would habituate in response to a repetitively applied mental stressor and whether cortisol reactivity would show a relationship with IL-6 reactivity. Study participants were 21 reasonably healthy men (mean age 46+/-7 years) who underwent the Trier Social Stress Test (combination of a 3-min preparation, 5-min speech, and 5-min mental arithmetic) three times with an interval of 1 week. Plasma IL-6 and free salivary cortisol were measured immediately before and after stress, and at 45 and 105 min of recovery from stress. Cortisol samples were also obtained 15 and 30 min after stress. Compared to non-stressed controls, IL-6 significantly increased between rest and 45 min post-stress (p=.022) and between rest and 105 min post-stress (p=.001). Peak cortisol (p=.034) and systolic blood pressure (p=.009) responses to stress both habituated between weeks one and three. No adaptation occurred in diastolic blood pressure, heart rate, and IL-6 responses to stress. The areas under the curve integrating the stress-induced changes in cortisol and IL-6 reactivity were negatively correlated at visit three (r=-.54, p=.011), but not at visit one. The IL-6 response to acute mental stress occurs delayed and shows no adaptation to repeated moderate mental stress. The hypothalamus-pituitary-adrenal axis may attenuate stress reactivity of IL-6. The lack of habituation in IL-6 responses to daily stress could subject at-risk individuals to higher atherosclerotic morbidity and mortality.
Acute Disease↗
Health-related quality of life, psychosocial work conditions, and absenteeism in an industrial sample of blue- and white-collar employees: a comparison of potential predictors.
PROBLEM: There is a scarcity of data simultaneously evaluating the relationship of health behavior, health perception, work characteristics, and demographic variables with sickness absenteeism in industrial employees. METHOD: Predictors and possible confounders (smoking, physical activity, alcohol intake, age, gender, body mass index, income) were regressed against frequency indices and the time lost index derived from the day-to-day absence data of 1524 employees at a manufacturing plant in Germany. Frequency indices were the number of sick-leave spells of 1, 2-3, 4-5, and >5 days within 1 year. RESULTS/CONCLUSION: Effort-reward imbalance, lack of support by supervisors or coworkers, negative affectivity, exhaustion, and impaired health perception were significantly associated with absence spells and the time lost index. Job demands and job control as well as overcommitment were unrelated to absenteeism indices. Multivariate models suggest mediation through impaired health-related quality of life.
Adaptation, Psychological↗
Alcohol use, urinary cortisol, and heart rate variability in apparently healthy men: Evidence for impaired inhibitory control of the HPA axis in heavy drinkers.
Alcoholism and heavy drinking are associated with a number of physiological, behavioral, affective, and cognitive problems. One such problem involves dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, with alcoholics showing higher basal cortisol levels and reduced inhibitory feedback control. In addition, alcohol consumption is associated with decreased heart rate variability (HRV). In the present study we examined the relationships among alcohol consumption, cortisol excretion, and HRV in 542 apparently healthy men. Men in the top tertile of self-reported alcohol consumption had higher cortisol levels and lower HRV compared to men in the lower two tertiles of alcohol consumption. In addition, the inverse relationship between cortisol and HRV was greatly attenuated in the heavy drinking group even after accounting for a number of potential confounding factors. These results support prior research on the HPA axis dysregulation in alcoholics and suggest impaired inhibitory control of the HPA axis in heavy drinkers. The findings are consistent with the neurovisceral integration model, which links central and peripheral processes, and may provide a comprehensive framework for the future investigation of the complex mix of physiological, behavioral, affective, and cognitive factors which comprise the heavy drinking phenotype.
Adolescent↗
Exhaustion is associated with reduced habituation of free cortisol responses to repeated acute psychosocial stress.
We investigated the association between exhaustion and the habituation of free cortisol responses to repeated stress exposure. The study comprised 25 healthy male subjects (38-59 years) who were confronted three times with the Trier Social Stress Test. Mean cortisol responses showed the well-known general habituation effect. A two-way interaction day by exhaustion (p<0.05) indicated that mean cortisol responses vary across stress sessions depending on the extent of exhaustion. Linear regression revealed a negative dose-response relationship between exhaustion and the degree of habituation (p<0.02). We identified 19 individuals showing a response habituation (negative slope) and 6 individuals showing a response sensitization over the three sessions (positive slope) with the latter reporting higher exhaustion scores. It might be hypothesized that impaired habituation to repeated exposure to the same stressor could reflect a state of increased vulnerability for allostatic load. Absence of normal habituation might be one potential mechanism how exhaustion relates to increased disease vulnerability.
Adult↗
Opposite effect of negative and positive affect on stress procoagulant reactivity.
Exaggerated procoagulant responses to acute mental stress may contribute to coronary thrombosis, and continuing low-grade systemic coagulation activation may link negative affect with the development of coronary artery disease. We investigated whether negative and positive affect and perceived social support would moderate stress procoagulant reactivity. Psychological functioning, exhaustion, negative affectivity, depression, anxiety, worrying, vigor, and social support were assessed in 27 apparently healthy men (mean age 47 +/- 8 years) who underwent the 13-min Trier Social Stress Test combining preparation, speech, and mental arithmetic. Plasma levels of von Willebrand factor antigen (VWF:Ag), fibrinogen, factor VII clotting activity (FVII:C), FVIII:C, FXII:C, and D-dimer were measured immediately before and after stress. Acute stress elicited significant increases in hemodynamic, cortisol, and coagulant activity (p values < 0.05). VWF:Ag reactivity showed inverse relationships with exhaustion (r = -0.63, p < 0.001), negative affectivity (r = -0.53, p = 0.005), and worrying (r = -0.53, p = 0.005). Exhaustion and negative affectivity emerged as independent predictors of VWF:Ag reactivity explaining 54% of its variance. Fibrinogen reactivity showed inverse relationships with negative affectivity (r = -0.59, p = 0.002) and anxiety (r = -0.54, p = 0.005); negative affectivity emerged as an independent predictor of fibrinogen reactivity explaining 35% of its variance. Psychological functioning and FVII:C reactivity were also correlated (r = -0.52, p = 0.006). Whereas FVIII:C reactivity correlated positively with vigorous mood (r = 0.48, p = 0.012), positive associations between social support and procoagulant reactivity did not reach significance. Negative affect was associated with attenuated procoagulant reactivity to stress and the opposite was observed for positive affect. Negative affect is not likely to enhance the acute procoagulant stress response in healthy men.
Adult↗
The effect of repeated acute mental stress on habituation and recovery responses in hemoconcentration and blood cells in healthy men.
Acute mental stress elicits hemoconcentration and polycytosis. We investigated whether haematological response to repeated acute mental stress would habituate and be sustained 45 min and 105 min after stress. Twenty-four men underwent a 13-min stressor three times, one week apart; hematological variables were measured at week one and three. Hematocrit, hemoglobin, leukocytes, lymphocytes, erythrocytes, and thrombocytes all increased from rest to immediately post-stress (p's<.001). After 105 min of recovery, leukocytes and platelets both were higher, and hematocrit, hemoglobin, lymphocytes, and erythrocytes were all lower than at rest (p's<.001 to <.05). At all time points, hematocrit (p=.005) and erythrocytes (p=.006) were lower at week three than at week one. In contrast to an attenuation in systolic blood pressure increase from rest to immediately post-stress (p<.001), and in cortisol recovery from immediately post-stress to 45 min post-stress (p<.001), the magnitude of change in hemoconcentration and cell counts in stress and recovery experienced no habituation. Adjustment for stress-induced plasma volume shift altered findings: Elevated leukocytes post-stress persisted at 105 min (p<.001); any changes in lymphocytes became insignificant; erythrocytes decreased from rest to post-stress (p<.001) to increase again during recovery (p's<.05); platelets increased linearly between rest and 105 min of recovery (p=.005). We conclude that the magnitude of changes in hemoconcentration and blood cells during acute mental stress and recovery failed to habituate to stress repeats and, in part, sustained up to 105 min. Plasma volume shift accompanying stress affects the time course of stress polycytosis.
Adult↗
Overcommitment to work is associated with vital exhaustion.
OBJECTIVES: Vital exhaustion has been shown to predict the progression and manifestation of cardiovascular disease. Little is known about the relationship between vital exhaustion and overcommitment, the inability to withdraw from obligations at work. The aim of this study was to explore the relationship between vital exhaustion and overcommitment at work, as measured by the intrinsic-effort scale of the effort-reward model after consideration of other potentially salutogenetic and pathogenetic working conditions. METHODS: This cross-sectional study is based on a stratified random sample of 634 employees (mean age 39.9 years, standard deviation 10.7 years) from a manufacturing and assembly plant for aeroplane parts. Participants completed a questionnaire, which included the nine-item shortened Maastricht exhaustion questionnaire to score the dependent variable exhaustion, and the six-item short form of the intrinsic-effort scale ("immersion") of the effort-reward-imbalance model as the primary independent variable. Perceived work stress was assessed by Siegrist's effort-reward-imbalance questionnaire and the 52-item, 13 subscale salutogenetic subjective work assessment (SALSA) questionnaire, which focuses on indicators of perceived work stress in terms of pathogenetic and salutogenetic descriptors of decision latitude, psychological job demands, and social support. Additional candidate covariates included depression, anxiety and type-D personality. RESULTS: In regression analysis, overcommitment (r=0.516; P<0.0001) was independently associated with vital exhaustion. Multivariable linear regression analysis showed that overcommitment explained 27% of the variance of vital exhaustion. CONCLUSIONS: Overcommitment, indicating an exhaustive work-related coping style, is independently associated with vital exhaustion. It appears to be an important personality trait that may contribute to feelings of exhaustion at times of increased job strain.
Adult↗
Relationship between hemoconcentration and blood coagulation responses to acute mental stress.
BACKGROUND: Acute mental stress elicits reliable changes in blood coagulation factors. We studied whether stress-related changes in coagulation measures are associated with concomitant hemoconcentration. METHODS: Twenty-two men (mean age 47+/-8 years) underwent the Trier Social Stress Test (TSST) combining 13 min of task preparation, job interview, and mental arithmetic. Venous blood was obtained immediately before the preparation phase and immediately after stress to determine seven measures of coagulation and three measures of hemoconcentration. RESULTS: Clotting factor VII activity (FVII:C; 99.5+/-21.9 vs. 104.5+/-23.7 IU; p=0.016), FVIII:C (96.3+/-18.1 vs. 105.1+/-25.7 IU; p=0.008), FXII:C (95.8+/-26.7 vs. 102.6+/-26.4 IU; p=0.002), and von Willebrand factor antigen (vWF; 103.3+/-36.3 vs. 110.1+/-43.3 IU; p=0.009) all increased from baseline to poststress, with a similar statistical trend observed for d-dimer (177.6+/-85.5 vs. 180.5+/-83.9 ng/ml; p=0.058). The absolute increases in fibrinogen and in soluble tissue factor were not significant. Hematocrit (40.8+/-2.5 vs. 42.7+/-2.8; p<0.001) and hemoglobin (14.5+/-0.81 vs. 15.2+/-0.97; p<0.001) increased, and plasma volume (59.2%+/-2.5 vs. 54.6+/-4.2%; p<0.001) decreased from baseline to poststress. Unlike with heart rate (HR) and blood pressure (BP) reactivity, there emerged no significant relationship between change scores in any hemoconcentration and coagulation measure (all r values<0.4, all p values>0.05). CONCLUSION: We corroborated significant changes in coagulation measures in response to acute mental stress compatible, with the notion that stress may elicit a hypercoagulable state. However, stress hemoconcentration appears not to explain a substantial proportion in coagulation changes elicited by acute mental stress.
Adult↗
Health-related quality of life measured by the SF12 in working populations: associations with psychosocial work characteristics.
This study investigated the contribution of psychosocial work characteristics (decision latitude, job demand, social support at work, and effort-reward imbalance) to health-related quality of life. Data were derived from 2 aircraft manufacturing plants (N=1,855) at the start of a longitudinal study. Regression analysis showed that work characteristics (1st model) explained 19% of the variance in the mental summary score of the Short Form-12 Health Survey. R2 change for work characteristics decreased to 13%, accounting for demographics, socioeconomic status, body mass index, and medical condition (5th model). Including health behavior and personality factors (full model), R2 change for work characteristics remained significant. Psychosocial work characteristics account for relevant proportions in the subjective perception of mental health beyond a wide array of medical variables and personality factors.
Adult↗
Different contribution of interleukin-6 and cortisol activity to total plasma fibrin concentration and to acute mental stress-induced fibrin formation.
Acute mental stress may contribute to atherosclerosis by affecting inflammation and coagulation; however, the crosstalk between inflammation and coagulation during stress has not been studied. In the present study, we investigated the association of plasma fibrinogen, plasma IL-6 (interleukin-6) and free salivary cortisol with the procoagulant marker D-dimer reflecting fibrin formation both over a 2-h period and in response to acute mental stress. Twenty-one male volunteers (mean age, 47+/-8 years) underwent the Trier Social Stress Test combining a 3-min preparation phase, a 5-min job interview and 5-min mental arithmetic test before an audience. IL-6, fibrinogen, D-dimer and cortisol were measured immediately before and after stress, and after 45 min and 105 min of recovery from stress. Two distinct areas under the curve were computed to obtain integrated measures of total protein activity over the entire 2-h period and of stress reactivity of proteins. IL-6 (P < 0.001), fibrinogen (P = 0.001), D-dimer (P = 0.021) and cortisol (P < 0.001) had all significantly changed across the four time points assessed, as determined by ANOVA. For the entire 2-h period, total fibrinogen activity (R2 = 0.33, P = 0.007) and total cortisol activity (DeltaR2 = 0.17, P = 0.034) explained 50% of the variance in total D-dimer activity. Stress-induced changes in fibrinogen (R2 = 0.47, P = 0.001) and IL-6 (DeltaR2 = 0.18, P = 0.008) together explained 65% of the variance in D-dimer reactivity to stress. Total fibrin formation was independently predicted by fibrinogen and hypothalamo-pituitary-adrenal activity. Pro-inflammatory and procoagulant changes with stress were associated. Aside from fibrinogen reactivity, IL-6 reactivity was an independent predictor of stress-induced fibrin formation.
Adult↗
Physicians' ability to diagnose sepsis in newborns and critically ill children.
OBJECTIVE: To elucidate physicians' ability to correctly diagnose infection in critically ill children in three different situations: 1) post hoc adjudication (e.g., ward rounds, outcome determination in surveillance studies or controlled trials), 2) when decisions must be made (e.g., sepsis workup in suspected infection), c) and applying suggested adult consensus conference definitions in children. METHOD: Appraisal of two previously published studies and a data simulation model. SETTING: Data of the reviewed studies were obtained from a multidisciplinary neonatal and a pediatric intensive care unit in tertiary hospitals. INTERVENTIONS: None. MAIN RESULTS: In the first study reviewed, the post hoc adjudication of 167 consecutive cases of suspected infection was carried out by a fifth-year medical student and three senior consultants. The agreement of the three experts beyond chance in the 119 episodes not classifiable unanimously by a priori defined criteria into proven sepsis or no infection was poor. In the second study reviewed, the physicians provided daily predictions of the likelihood of infection (pretest probability) in premature infants and critically ill children (2567 hospitalization days). Estimated pretest probabilities provided at the time of sepsis workup showed a remarkable predictive accuracy (area under the receiver operating characteristic curve, 0.85). In the simulation model, in which catheter-related sepsis was assumed, correct classification of patients from a central and a peripheral culture decreased to 56% when a sensitivity of 70%-80% was assumed for blood cultures and amounted to 15% only when a sensitivity of 30%-50% was imputed. CONCLUSION: Misclassification is a serious threat in post hoc adjudication of episodes or when consensus definitions rely on the application of criteria with imperfect sensitivity (e.g., the positivity of blood cultures in premature infants or children). This underscores the need to use probability-based categorizations such as probable and possible infection.
Biomarkers↗
Non-somatic effects of patient aggression on nurses: a systematic review.
AIM: This paper describes a systematic review of the predominant non-somatic effects of patient assault on nurses. Background. Patient aggression towards nurses is a longstanding problem in most nursing domains. Although reports on the consequences of physical aggression are more numerous, the non-physical effects create much suffering. METHOD: A systematic review of literature from 1983 to May 2003 was conducted using the Medline, CINAHL, PsychINFO and PSYINDEX databases. Articles from international journals in English or German and reporting at least three non-somatic responses to patient aggression were included. FINDINGS: The electronic search produced 6616 articles. After application of the inclusion and exclusion criteria, 25 texts from eight countries and four domains of nursing remained. Twenty-eight main effects were found, and these were categorized using a system suggested by Lanza and including bio-physiological, emotional, cognitive, and social dimensions. The predominant responses were anger, fear or anxiety, post-traumatic stress disorder symptoms, guilt, self-blame, and shame. These main effects occurred across most countries and nursing domains. CONCLUSION: Despite differing countries, cultures, research designs and settings, nurses' responses to patient aggression are similar. Standardized questionnaires could help improve estimations of the real prevalence of non-somatic effects. Given the suffering caused by non-somatic effects, research should be aimed at preventing patient aggression and at developing better ways to prepare nurses to cope with this problem.
Aggression↗
The Impact of Patient Aggression on Carers Scale: instrument derivation and psychometric testing.
Patient aggression towards carers constitutes a problem for patients and carers alike. Patients' aggressive behaviour often leads to adverse consequences for carers, especially nurses. Various extensive instruments have been developed to measure such adverse effects on carers. The 'Impact of Patient Aggression on Carers Scale' (IMPACS) is a short instrument intended for use in monitoring negative consequences of such incidents. The items of the IMPACS were derived basically from a review of the literature on negative effects of patient aggression on nurses. The IMPACS was administered to a convenience sample of nurses working on 14 psychiatric acute admission wards in the German speaking part of Switzerland. Factor analysis led to the exclusion of three of the original items and to an interpretable three-factor solution with all factors demonstrating eigen values higher than 1. The factors demonstrate moderate to good internal consistency. Canonical correlation analysis using the dimensions of the Maslach Burnout Inventory (MBI) produced a correlation coefficient of 0.457, thus demonstrating external reliability. In spite of some caveats such as possible response bias and the necessity of the investigation of the test-retest stability of the scale this study suggests that the IMPACS is a good measure of adverse effects and thus merits further development.
Adult↗
The effect of a training course on nursing students' attitudes toward, perceptions of, and confidence in managing patient aggression.
Patient aggression is a problem in many health care settings, and nursing students are among the most vulnerable to experiencing such aggression. Training courses have been suggested to help nurses better manage patient aggression. Such courses can lead to changes in attitudes toward and perceptions of, as well as greater confidence in managing, aggression. In this quasi-experimental study, we investigated the effect of a training course on nursing students' attitudes toward, perceptions of, and confidence in managing patient aggression. Students in the intervention group demonstrated enhanced confidence but no change in attitude after the training course, while students in the control group remained stable on all measures. The short time frame of the study, the training course itself, and the instruments used for monitoring attitudes toward aggression are possible reasons for these results. We tentatively conclude that it is possible to enhance nursing students' perceived confidence in managing patient aggression without changing their fundamental views of it.
Adaptation, Psychological↗
G-CSF and IL-8 for early diagnosis of sepsis in neonates and critically ill children - safety and cost effectiveness of a new laboratory prediction model: study protocol of a randomized controlled trial [ISRCTN91123847].
INTRODUCTION: Bacterial infection represents a serious risk in neonates and critically ill paediatric patients. Current clinical practice is characterized by frequent antibiotic treatment despite low incidence of true infection. However, some patients escape early diagnosis and progress to septic shock. Many new markers, including cytokines, have been suggested to improve decision making, but the clinical efficacy of these techniques remains uncertain. Therefore, we will test the clinical efficacy of a previously validated diagnostic strategy to reduce antibiotic usage and nosocomial infection related morbidity. METHODS: All patients admitted to the multidisciplinary neonatal and paediatric intensive care unit of a university children's hospital will be included. Patients will be allocated either to routine sepsis work up or to the intervention strategy with additional cytokine measurements. Physicians will be requested to estimate the pre-test probability of sepsis and pneumonia at initial suspicion. In the treatment arm, physicians will receive raw cytokine results, the likelihood ratio and the updated post-test probability. A high post-test probability will suggest that immediate initiation of antibiotic treatment is appropriate, whereas a low post-test probability will be supportive of watchful waiting or discontinuing prophylactic empirical therapy. Physicians may overrule the suggestions resulting from the post-test probability. CONCLUSION: This trial will ascertain the clinical efficacy of introducing new diagnostic strategies consisting of pre-test probability estimate, novel laboratory markers, and computer-generated post-test probability in infectious disease work up in critically ill newborns and children.
Anti-Bacterial Agents↗
Effect of the G-308A polymorphism of the tumor necrosis factor (TNF)-alpha gene promoter site on plasma levels of TNF-alpha and C-reactive protein in smokers: a cross-sectional study.
BACKGROUND: Plasma levels of tumor necrosis factor (TNF)-alpha and of C-reactive protein (CRP) are elevated in smokers. Previous studies failed to show an association between the G-308A polymorphism in the promoter region of the TNF-alpha gene and coronary artery disease (CAD). We investigated whether smoking would interact with the TNF-alpha G-308A polymorphism in determining plasma levels of TNF-alpha and CRP. METHODS: Study participants with a complete data set in terms of smoking and the TNF-alpha G-308A polymorphism were 300 middle-aged male and female industrial employees. After excluding 24 irregular smokers, analyses were performed on 198 "non-smokers" (life-long non-smokers or subjects who quit smoking >6 months ago) as compared to 78 "regular smokers" (subjects currently smoking >3 cigarettes/day). All subjects had a fasting morning blood draw to measure plasma levels of TNF-alpha and CRP by high-sensitive enzyme-linked immunosorbent assays. RESULTS: The cardiovascular risk factor adjusted analysis regressing log-transformed CRP levels against smoking status, genotype, and smoking-status-genotype interaction revealed a significant main effect for smoking status (F1,250 = 5.67, p = .018) but not for genotype (F1,250 = 0.33, p = .57). The interaction-term between genotype and smoking status was not significant (F1,250 = 0.09, p = .76). The fully adjusted model with plasma TNF-alpha failed to show significant main effects for smoking and genotype, as well as for the smoking-status-genotype interaction. CONCLUSIONS: The findings suggest that the TNF-alpha G-308A polymorphism does not mediate the effect of smoking on plasma CRP levels. It remains to be seen whether other genetic polymorphisms along the inflammatory pathway may modulate vascular risk in smokers.
C-Reactive Protein↗