Die wissenschaftliche Erforschung des Haushundes (Canis lupus forma familiaris) mit Fokus auf seine sozialen Eigenschaften hat große Relevanz in Anbetracht seiner zunehmenden Bedeutung im Zusammenleben mit dem Menschen als Familienmitglied und Arbeitstier. Ziel der vorliegenden Studie war es, die Relevanz von Dominanz in den Beziehungen von Gruppenmitgliedern einer Meute Englischer Foxhounds darzustellen sowie ihre Auswirkung auf die Sozialstruktur der Hunde. Weitergehend sollte die Analyse von aggressionsanzeigendem Verhalten und sozialen Strategien Aufschluss über Regelungsmechanismen im Zusammenleben der Hunde geben. Speichelcortisolanalysen sollten Einblick über die Stressexposition der Hunde in diesem Zusammenleben geben. Das Neutrophilen/ Lymphozyten Verhältnis im Blut sollte darüber hinaus mögliche Auswirkungen der Cortisolproduktion auf das Immunsystem aufzeigen. Für die Datenerhebung wurden 16 Englische Foxhounds einer Meute von 72 Hunden berücksichtigt. Je 4 Hündinnen und 4 Rüden wurden einer von 2 Gruppen zugeteilt. Über einen Zeitraum von 10 Monaten erfolgten Verhaltensbeobachtungen an jedem Individuum mittels der Methode Focal Animal Sampling. Von Hunden aus Gruppe 1 wurden 17,5 Stunden Beobachtungsmaterial und aus Gruppe 2 17,0 Stunden gesammelt. Die Speichelproben wurden mit der Salivette® der Firma SARSTEDT (Nümbrecht- Rommelsdorf) entnommen und mittels eines speziell für die Speichelcortisol- Analyse entwickelten Immunoassays (double- antibody biotin- linked enzyme immunoassay) analysiert. Ergebnisse: Die als möglicherweise dominanzanzeigend eingestuften Indikatoren, nämlich die Körperhaltung High Posture und die Durchsetzungskraft als Eigenschaft eines Hundes, konnten als solche nicht bestätigt werden. Es konnte keine dominanzbasierte Hierarchie ermittelt werden. Auch konnten von 82 Dyaden nur in 5 eine Dominanz- Subordinanz- Beziehung ermittelt werden, was kein aussagekräftiges Ergebnis darstellt. Aggressive Handlungen wurden in beiden Gruppen pro Stunde durchschnittlich jeweils 12 Mal beobachtet, jedoch meist in der Intensität 1 - 2 (von 5- stufiger Skala). Sie wurden hochsignifikant häufiger unter Rüden als unter Hündinnen beobachtet (p= 0,002). Berechnungen der Aggressionskoeffizienten belegten deutliche Unterschiede in den individuellen Aggressionsniveaus. Die Analyse ausgetragener Konflikte auf Taktiken und Strategien lieferte jedoch keine signifikanten Ergebnisse. Die Foxhounds reagierten situativ und selten gegner- und nie kontextabhängig. Die Speichelcortisolanalysen belegten vielfach höhere Basal- Mittelwerte der Foxhounds verglichen mit Analysen von Hunden anderer Studien. Eine Reduktion des Cortisolwerts erfolgte bei 14 von 16 Hunden nach 20- minütigem Einzelspaziergang mit Menschenkontakt. Allerdings konnte keine Verbindung zwischen dem Speichelcortisolwert und dem soziometrisch errechneten Rangplatz in der Gruppe ermittelt werden. Ebenso bestand keine Korrelation zwischen dem Speichelcortisolwert und Immunstatus sowie Aggressionspotential. Schlussfolgerungen: Dominanz spielte keine erkennbare Rolle in den sozialen Interaktionen und Beziehungen der Hunde. Die Ergebnisse lassen die Schlussfolgerung auf eine egalitäre Sozialstruktur der Foxhounds zu statt einer dominanzabhängigen, was auch durch die situativ geregelten Begegnungen unterstützt wird. Aggressives Verhalten als häufig repräsentiertes Kommunikationselement wurde bei den einzelnen Hunden unterschiedlich oft beobachtet, was auf die Verschiedenheit der Charaktere und ihre Motivationen, Konflikte einzugehen, hindeutet. Die häufiger unter Rüden beobachtete Aggression kann auf ein erhöhtes Konkurrenzpotential hindeuten. Die im Speichel der Foxhounds gemessenen Cortisolwerte lassen die Vermutung auf eine durch das Gruppenleben bedingte Erhöhung des Basalwerts zu, ohne Konsequenzen auf den Immunstatus. Die fehlenden Korrelationen zu den individuellen Rangplätzen und Aggression unterstützt die Vermutung eines lockeren bzw. egalitären Sozialgefüges.

Moderne Theorien der Verhaltenskontrolle unterscheiden zwei Systeme, wobei das Handeln gesunder Individuen von beiden geprägt ist: Das retrospektiv agierende habituelle, sog. modellfreie Verhalten zeichnet sich durch Wiederholung zuvor belohnter Entscheidungen aus. Es passt sich nur langsam an möglicherweise veränderte Umweltbedingungen an. Die verstärkte Nutzung des habituellen Systems gilt als assoziiert mit verschiedenen psychischen Erkrankungen. Dem gegenüber steht das zielgerichtete, sog. modellbasierte Verhalten, das sich durch vorausschauende Entscheidungen auszeichnet. Hierbei werden die möglichen Konsequenzen einer Handlung berücksichtigt, um ein gewünschtes Ergebnis zu erreichen. Dazu wird ein „mentales“ Modell der Umwelt- bedingungen erstellt. In einer Verhaltensstudie mit 39 Versuchspersonen wurde untersucht, ob biopsychologischer Stress zu einer Reduktion von modellbasiertem hin zu mehr modellfreiem Verhalten führt. Dazu absolvierten 39 Versuchspersonen eine sequentielle Entscheidungsaufgabe, nachdem sie psychosozialem Stress ausgesetzt wurden. Subjektive und physiologische Stress-Parameter wurden über das Experiment hinweg wiederholt erhoben. Ein direkter Effekt von akutem Stress auf das Gleichgewicht modellfreien vs. modellbasierten Verhaltens konnte nicht beobachtet werden. Allerdings zeigten diejenigen Versuchspersonen, die in den letzten zwei Jahren eine hohe Anzahl an stressbehafteten Lebensereignissen aufwiesen (chronischer Stress), signifikant weniger modellbasiertes Verhalten nach der Exposition von akutem Stress als in der Kontrollbedingung. Darüber hinaus korrelierte physiologische Stressreaktivität (stressbedingte Cortisol- Ausschüttung) negativ mit modellbasiertem Entscheidungsverhalten, während subjektive Stressreaktivität (basierend auf Fragebögen) positiv mit modellbasiertem Verhalten assoziiert war. Der in der Forschung beschriebene Einfluss von akutem und chronischem Stress auf die Entstehung und Aufrechterhaltung psychischer Erkrankungen könnte demnach teilweise über ein solches Ungleichgewicht der beiden Entscheidungsstrategien vermittelt sein.

Allergic manifestations are increasingly common in infants and children. Accumulating evidence suggests that the ‘epidemic’ increase of childhood allergy may be associated with environmental factors such as stress. Although the impact of stress on the manifestation and exacerbation of allergy has been demonstrated, the underlying mechanisms of stress-induced exacerbation are still obscure. A growing number of studies have suggested an altered hypothalamus-pituitary-adrenal (HPA) axis function to stress in allergic children. It is speculated that a dysfunctional HPA axis in response to stress may facilitate and/or consolidate immunological aberrations and thus, may increase the risk for allergic sensitization and exacerbation especially under stressful conditions. In the present review the potential impact of a hyporesponsive as well as a hyperresponsive HPA axis on the onset and chronification of childhood allergy is summarized. Moreover, potential factors that may contribute to the development of an aberrant HPA axis responsiveness in allergy are discussed. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Le trouble du spectre de l’autisme se caractérise par la présence de difficultés au plan de la communication sociale et par la présence de comportements répétitifs et d’intérêts restreints (American Psychiatric Association, 2013). Les enfants ayant un TSA présentent plusieurs difficultés concomitantes qui les rendent plus susceptibles de vivre des niveaux de stress élevés, comme des déficits dans la sphère de la communication, de la socialisation et des fonctions exécutives, ainsi que la présence de particularités sensorielles (Groden et al., 1994, 2005). Malgré que ces enfants soient plus à risque de vivre du stress, plusieurs enjeux méthodologiques rendent difficile sa mesure et plus particulièrement chez ceux qui sont non verbaux. Pour ces raisons, le recours aux mesures physiologiques pour évaluer le stress auprès de cette clientèle est d’une grande pertinence. Par contre, les sensibilités sensorielles de ces enfants pourraient les rendre plus susceptibles de ne pas tolérer ces mesures. Le premier article de cette thèse vise donc à évaluer l’efficacité de l’intervention comportementale renforcement différentiel d’autres comportements (differential reinforcement of other behavior; DRO) pour augmenter la tolérance au port d’une ceinture cardiaque chez deux enfants non verbaux ayant un TSA. Les résultats obtenus démontrent que cette intervention a été efficace pour amener ces enfants à augmenter leur tolérance au port du dispositif cardiaque. Un autre aspect qui a reçu beaucoup d’attention dans les dernières années est l’implication du stress dans l’explication des comportements répétitifs et stéréotypés chez les personnes ayant un TSA. Les résultats des études antérieures sont contradictoires (de Vaan et al., 2018; Gabriels et al., 2013; Hutt et al., 1975; Lydon et al., 2015; Yang et al., 2015) et ont principalement utilisé des mesures indirectes des comportements répétitifs. Pour cette raison, le deuxième article de cet ouvrage vise à évaluer le lien entre le cortisol salivaire, le rythme cardiaque et des mesures d’observations directes de la stéréotypie chez quatre enfants minimalement verbaux ayant un TSA. Les résultats montrent que le cortisol et le rythme cardiaque sont significativement liés à la stéréotypie globale et motrice, sans que ces liens soient observés avec la stéréotypie vocale. Finalement, mesurer directement les comportements stéréotypés demande beaucoup de ressources, ce qui pourrait expliquer la prépondérance des mesures indirectes dans les études. Comme pour l’évaluation du stress, il importe de réfléchir aux méthodes alternatives abordables et accessibles qui pourraient améliorer la mesure de ces comportements. Le troisième article de cette thèse a évalué l’efficacité d’un algorithme d’intelligence artificielle (IA) dans la reconnaissance de la stéréotypie vocale chez des enfants ayant un TSA. Les résultats démontrent que la performance de l’algorithme est supérieure à la reconnaissance due au hasard. Bien que des recherches futures soient nécessaires pour augmenter l’efficacité de cette méthode, l’IA représente une technologie novatrice ayant le potentiel d’améliorer significativement les méthodes actuellement utilisées pour mesurer la stéréotypie. En conclusion, le présent ouvrage explore différentes avenues novatrices pour mieux comprendre et de monitorer la stéréotypie chez les enfants ayant un TSA. / Autism spectrum disorder (ASD) is characterized by the presence of difficulties in social communication and the presence of repetitive behaviors and restricted interests (American Psychiatric Association, 2013). Children with ASD have several concurrent difficulties, such as deficits in communication, socialization, and executive function, as well as the presence of sensory peculiarities that make them more likely to experience high levels of stress (Groden et al., 2005). Although these children are at increased risk for stress, a number of methodological issues make it difficult to measure, particularly in non-verbal children. For these reasons, the use of physiological measures to assess stress among this group is highly relevant. On the other hand, the sensory sensitivities of these children could potentially make them more likely to be intolerant to these measures. Therefore, the first study in this thesis aims to evaluate the effectiveness of differential reinforcement of other behavior (DRO) to increase compliance with wearing a heart rate monitor in two non-verbal children with ASD. The results obtained portray that this intervention was effective in getting these children to increase their compliance to wearing a cardiac device. Another aspect that has received much attention in recent years is the involvement of stress in explaining repetitive behaviors in individuals with ASD. However, the results of previous studies have been producing contradictory results (de Vaan et al., 2018; Gabriels et al., 2013; Hutt et al., 1975; Lydon et al., 2015; Yang et al., 2015), and have mainly been using indirect measures of stereotypy. For this reason, the second study in this thesis aims to evaluate the relationship between salivary cortisol, heart rate, and direct observational measures of stereotypy in four minimally verbal children with ASD. The results show that cortisol and heart rate are significantly related to global and motor stereotypy, but not to vocal stereotypy. Finally, measuring stereotypy requires a lot of resources, which could explain the preponderance of indirect measuring in studies on stress. As with the measurement of stress, it is important to consider affordable and alternative methods that could improve the measurement of these behaviors, and therefore the third study evaluated the effectiveness of an artificial intelligence (AI) algorithm in the recognition of vocal stereotypy in children with ASD. The results show that the performance of the algorithm is superior to recognition due to chance. Although future research is needed to increase the effectiveness of this method, AI represents an innovative technology with the potential to significantly improve the methods currently used to measure vocal stereotypy. In conclusion, this thesis explores different innovative methods to better understand and monitor stereotypy in children with ASD.

Summary: Salivary alpha-amylase: More than an enzyme - Investigating confounders of stress-induced and basal amylase activity (Dipl.-Psych. Jana Strahler) The hypothalamus-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) are two of the major systems playing a role in the adaptation of organisms to developmental changes that threaten homeostasis. The HPA system involves the secretion of glucocorticoids, including cortisol, into the circulatory system. Numerous studies have been published that introduced salivary cortisol to assess HPA axis activity and therefore strengthens its role as an easy obtainable biomarker in stress research that can be monitored easily and frequently. Recent findings suggest a possible surrogate marker of autonomic activity due to autonomic innervation of salivary glands: salivary alpha-amylase (sAA). Up to date, additional methodological research is needed for a better understanding of the advantages and disadvantages of sAA activity in comparison to already established markers of ANS activity. The aim of the present thesis is to further our knowledge of confounders of sAA activity under basal and acute stress conditions and to strengthen the validity of this enzyme as an easy obtainable alternative for ANS testing. After introducing classical and modern stress concepts and stress system physiology (chapter 2), the reader is acquainted with anatomical basics of salivary gland innervation and secretion of salivary proteins, including sAA, due to autonomic innervation (chapter 3 and 4). Afterwards, a more nuanced review of methodological considerations of sAA determination shows gaps of knowledge concerning its usefulness as a marker of ANS activity (chapter 5). Given the fact that the integration of sAA into developmental and aging research is a relative recent phenomenon, several issues have to be addressed before a final conclusion could be drawn. Therefore, we conducted a series of studies incorporating these considerations regarding behavioral correlates of inter- and intraindividual differences in sAA activity with a special emphasis on older adults. Chapter 7 deals with sAA activity under psychological stress conditions in different age groups. Since vulnerability to disease and disease prevalence patterns change with age, it is important to investigate stress reactivity of people in different age groups. We therefore investigated children between 6 and 10 years, because childhood is a sensitive period of growth and development, and thus plays an important role for later life health. Young adults were included to represent the most studied human age group as a reference. Older adults between 59 and 61 years were investigated, because at this age the course is set for the further development of a person’s health in later life, and because autonomic stress responses in older age might be important determinants of cardiovascular and inflammatory aging. Our goal is to test for associations of sAA with more established stress system markers, i.e., salivary cortisol as outcome measurement of HPA reactivity, heart rate (HR) and heart rate variability (HRV) as markers for autonomic reactivity, and to directly compare these responses between different age groups across the life span. Secretion of sAA and cortisol was repeatedly assessed in 62 children, 78 young adults, and 74 older adults after exposure to a standardized psychosocial stressor, the Trier Social Stress Test. In addition, cardiovascular activity was measured in both adult groups. Older adults showed attenuated sAA, HR, and HRV responses. Furthermore, we found higher sAA but lower cortisol at baseline as well as lower sAA and cortisol responses in children. Age by sex interactions were observed only for cortisol with higher responses in older male participants. No associations between the parameters were found. Results in children and young adults confirm previous results. Overall, findings implicate sAA as an alternative or additional autonomic stress marker throughout the life span, with marked and rapid responsiveness to stress in three relevant age groups. The impact of age and chronic stress on basal sAA activity is the center of interest in chapter 8. We therefore assessed diurnal profiles of sAA and salivary cortisol in 27 younger and 31 older competitive ballroom dancers as well as 26 younger and 33 older age- and sex-matched controls. According to the Allostatic Load concept, repeated, non-habituating responses to social-evaluative conditions, which characterize the lives of competitive ballroom dancers, should be associated with stress system dysregulations. Furthermore, we expect to see an increased sympathetic drive associated higher overall alpha-amylase activity in older adults. Analyses revealed an elevated daily overall output of sAA in older adults while there was no effect of age on mean cortisol levels. Alterations of diurnal rhythms were only seen in younger male dancers showing a flattened diurnal profile of sAA and younger dancers and female older dancers showing a blunted diurnal rhythmicity of cortisol. Furthermore, we found a negative correlation between summary indices of basal sAA and the amount of physical activity. In conclusion, higher overall output of sAA in older adults was in line with the phenomenon of a “sympathetic overdrive” with increasing age. Furthermore, a lower output of sAA in people who are more physical active was in line with the hypothesis of an exercise-induced decrease of sympathetic activity. Taken together, results of chapter 7 and 8 show a clear impact of age on sAA activity, either under acute stress or basal conditions. One problem when integrating sAA into developmental and aging research is the use of adrenergic agonists and antagonists what is very common in older adults, i.e. antihypertensive drugs (AD). As well, the previously shown sympathetic overactivity that occurs with normal aging is associated with higher blood pressure (BP). Therefore, chapter 9 deals with a possible impact of high BP and AD on diurnal sAA activity in 79 older adults (33 normotensive adults, 16 medicated vs. 45 hypertensive adults, 34 medicated). Results showed a pronounced rhythm of sAA in all groups. Diurnal profiles differed significantly between men and women with men lacking the typical decrease of sAA in the morning and showing more pronounced alterations throughout the day. An effect of AD on sAA profiles and area under the curve values indicates that subjects not using AD´s show a heightened diurnal profile and a higher total output of sAA. Descriptively, this was also true for hypertensive older adults. Hypertensive subjects and those not using AD showed the highest diurnal output of sAA and the steepest slope. In sum, our results show an impact of antihypertensive medication and a difference between normotensive and hypertensive subjects on characteristics of diurnal sAA activity. Hence, findings are of particular interest in research using sAA as a prognostic indicator of pathological states and processes. Given the fact that hypertension was also shown to be associated with substantial changes of transmitters within the suprachiasmatic nucleus (SCN) - the “biological clock” that receives photic input from retinal glands via the retinohypothalamic pathway - and an altered output from the SCN to the sympathetic nervous system, we broaden the idea of a possible effect of different lighting conditions on morning sAA profiles in chapter 10. In a counterbalanced within-subjects design six men and 16 women of different ages collected sAA morning profiles on two consecutive days with leaving their shutters closed on the one day (= dark) and open their shutters on the other day (= bright). We were able to replicate earlier findings of light-induced changes of salivary cortisol with higher responses during the bright condition. On either day, women showed larger cortisol increases than men. Despite multisynaptic autonomic connections arising from the SCN projecting to multiple organs of the body, we could not find an effect of sunlight on sAA morning profiles. Evidence for circadian clock gene expression in human oral mucosa might account for this result and indicates that peripheral oscillators may act more like integrators of multiple different time cues, e.g. light, food intake, instead of a “master” oscillator (SCN). Results of chapter 7 to 10 provide clear evidence that sAA is heightened in states of autonomic arousal, i.e. stress, aging and hypertension, and that its circadian rhythmicity seems to be regulated rather integrative than directly via efferent input from hypothalamic SCN neurons. In chapter 11 this thesis tries to approach one central question: What is the biological meaning of the findings made? According to this enzyme´s anti-bacterial and digestive action short term changes might not have a biological meaning itself but rather reflect just a small part of multiple coordinated body responses to stressful stimuli. While the sympathetic branch of the ANS mainly stimulates protein secretion, the parasympathetic branch stimulates saliva flow. Acute stress responses might therefore be interpreted as reflecting predominant sympathetic activity together with parasympathetic withdrawal. The same mechanism could also be suitable for the finding of higher diurnal levels of sAA in older adults or hypertensive subjects reflecting a higher peripheral sympathetic tone in these groups. Diurnal profiles of sAA itself may reflect circadian changes in autonomic balance. Circadian rhythms are of great advantage since they enable individuals to anticipate. This pre-adaptation enables the individual to cope with upcoming demands and challenges. Our finding of a relationship between sAA and salivary cortisol what strengthens the relevance of glucocorticoids that were previously shown to be able to phase shift circadian rhythms in cells and tissue. Within a food-related context there is evidence that decreasing levels of sAA in the morning could reflect increases of feeling hungry since sAA systematically increases during food consumption and with the subjective state of satiety. So far, much more research is needed to identify underlying physiological mechanisms of circadian sAA rhythmicity. Taking the next step, future studies will have to focus on the integration of sAA assessment into longitudinal studies and different disease states to prove its applicability as a marker of sympathetic neural functioning in the genesis and prognosis of disease.:Table of Contents 1. Introduction 1 2. Stress 3 2.1. Stress concepts 3 2.1.1. Traditional concepts of stress 3 2.1.2. Allostasis and Allostatic Load 4 2.2. Stress system physiology 6 2.2.1. The hypothalamic-pituitary-adrenal (HPA) axis 6 2.2.1.1. Physiology 6 2.2.1.2. HPA axis activity indicators 6 2.2.2. The autonomic nervous system (ANS) 7 2.2.2.1. Physiology 7 2.2.2.2. ANS activity indicators 8 2.2.3. Relationships between stress systems 10 3. Saliva and salivary glands 11 3.1. Physiology 11 3.1.1. Anatomy, origin, and composition 11 3.1.2. Innervation 12 3.1.3. Salivary gland physiology with aging 13 3.2. Saliva and salivary flow 13 3.3. Protein secretion 14 4. Alpha-amylase in saliva 15 4.1. Chemical characteristics 15 4.2. Secretion of alpha-amylase 15 4.3. Diagnostic value of alpha-amylase 16 5. Methodological considerations of alpha-amylase determination 17 5.1. Collection methods and preparation 17 5.1.1. Saliva collection 17 5.1.2. Impact of flow rate 17 5.1.3. Impact of pH-value 18 5.2. Biochemical determination 18 5.3. Interindividual differences in sAA activity 19 5.3.1. Basal activity 20 5.3.2. Acute responses 20 5.3.3. Age effects 21 5.3.3.1. Basal amylase activity 21 5.3.3.2. Stress-induced amylase activity 21 5.3.4. Sex differences 22 5.3.4.1. Basal amylase activity 22 5.3.4.2. Stress-induced amylase activity 23 5.3.5. Modulating factors influencing amylase (re-)activity 24 5.3.5.1. Impact of smoking 24 5.3.5.2. Impact of alcohol 25 5.3.5.3. Impact of caffeine 25 5.3.5.4. Impact of high body fat and obesity 26 5.3.5.5. Impact of food intake 26 5.3.5.6. Impact of physical exercise 27 5.3.5.7. Impact of somatic and psychiatric diseases 27 5.3.5.8. Impact of medical drugs 29 5.3.5.9. Impact of sunlight on diurnal amylase 29 6. Aims and outline of the present work 31 7. Salivary alpha-amylase stress reactivity across different age groups 32 7.1. Introduction 32 7.2. Methods 35 7.2.1. Participants 35 7.2.2. Study Protocol 35 7.2.3. Measures 36 7.2.3.1. Saliva sampling 36 7.2.3.2. Heart rate and heart rate variability 36 7.2.3.3. Biochemical analyses 37 7.2.3.4. Psychometrical analyses 37 7.2.4. Statistical analyses 38 7.3. Results 38 7.3.1. Sample characteristic 38 7.3.2. Subjective stress response 39 7.3.3. Physiological stress response 39 7.3.3.1. Salivary alpha-amylase 39 7.3.3.2. Salivary cortisol 40 7.3.3.3. Heart rate 42 7.3.3.4. Heart rate variability 43 7.3.3.5. Determinants of the salivary alpha-amylase stress response 45 7.4. Discussion 45 7.5. Conclusion 48 8. Aging diurnal rhythms and chronic stress: Distinct alteration of diurnal rhythmicity of salivary alpha-amylase and cortisol 49 8.1. Introduction 49 8.2. Methods 52 8.2.1. Participants 52 8.2.2. Study protocol 53 8.2.3. Measures 53 8.2.3.1. Saliva sampling 53 8.2.3.2. Biochemical parameters 54 8.2.3.3. Psychological parameters 54 8.2.4. Statistical analyses 54 8.2.4.1. Preliminary analyses 54 8.2.4.2. Diurnal course of salivary alpha-amylase 55 8.3. Results 56 8.3.1. Sample characteristic 56 8.3.2. Preliminary analyses: impact of oral contraceptives, blood pressure, and lipid lowering medication on diurnal profiles 56 8.3.3. Diurnal course of salivary alpha-amylase 57 8.3.3.1. Salivary alpha-amylase over the day 57 8.3.3.2. Salivary alpha-amylase after awakening 58 8.3.4. Diurnal course of salivary cortisol 59 8.3.4.1. Salivary cortisol over the day 59 8.3.4.2. Salivary cortisol after awakening 60 8.3.5. Diurnal course of salivary biomarkers: associations and determinants 61 8.4. Discussion 62 8.5. Conclusion 65 9. Impact of blood pressure and antihypertensive drugs on diurnal alpha-amylase activity: A novel marker of sympathetic drive 67 9.1. Introduction 67 9.2. Methods 68 9.2.1. Participants 68 9.2.2. Study protocol 69 9.2.3. Measures 69 9.2.3.1. Saliva sampling 69 9.2.3.2. Biochemical parameters 69 9.2.3.3. Blood pressure assessment 70 9.2.4. Statistical analyses 70 9.3. Results 70 9.3.1. Participants 70 9.3.2. Salivary alpha-amylase 71 9.3.2.1. Salivary alpha-amylase over the day 71 9.3.2.2. Salivary alpha-amylase after awakening 74 9.4. Discussion 75 9.5. Perspectives 76 10. Light affects morning salivary cortisol, but not salivary alpha-amylase 77 10.1. Introduction 77 10.2 Methods 79 10.2.1. Participants 79 10.2.2. Study protocol 80 10.2.3. Measures 80 10.2.3.1. Saliva sampling 80 10.2.3.2. Biochemical parameters 81 10.2.4. Statistical analyses 81 10.3. Results 82 10.3.1. Sociodemographics 82 10.3.2. Salivary alpha-amylase 82 10.3.3. Salivary cortisol 84 10.3.4. Associations between biochemical parameters 85 10.4. Discussion 86 10.5. Conclusion 89 11. General discussion 90 11.1. Summary of the results 90 11.1.1. Salivary alpha-amylase stress reactivity across different age groups 91 11.1.2. Aging diurnal rhythms and chronic stress: Distinct alteration of diurnal rhythmicity of salivary alpha-amylase and cortisol 91 11.1.3. Impact of blood pressure and antihypertensive drugs on diurnal alpha-amylase activity: A novel marker of sympathetic drive 92 11.1.4. Light affects salivary morning cortisol, but not salivary alpha-amylase 93 11.2. Integration of main findings 93 11.3. Stress-induced amylase activity, basal rhythm, and its biological meaning 95 11.4. Methodological consequences 97 11.4.1. Circadian variation 97 11.4.2. Longitudinal variation 98 11.4.3. Short-term variation and stability 98 11.4.4. Long-term change 99 11.5. Outlook 100 12. References 102

Da topische Glucocorticoide im Vergleich zur parenteralen Anwendung weniger systemische (Neben)Wirkungen haben können, werden sie bevorzugt in der Human- und Veterinärmedizin eingesetzt. Jedoch konnte bei vielen Untersuchungen gezeigt werden, dass topische Glucocorticoide je nach Applikationsdauer, -ort, Wirkstoffpotenz, -dosis und Behandlungsfläche ausgeprägte messbare Reaktionen wie Suppression der HHNA und der Immunzellen hervorrufen können. Beim Pferd wurden jedoch dahingehend bisher keine Untersuchungen durchgeführt. Da Glucocorticoide im Pferdesport auch dopingrelevant sind wurde der Frage nachgegangen, ob nach der dermalen Applikation eines niederpotenten Glucocorticoidpräparates auf die Haut gesunder Pferde systemische Effekte auftreten können und ob ein, nach perkutaner Resorption auftretender, Wirkstoffspiegel im Blut gemessen werden kann. Im Rahmen dieser Dissertation standen 10 erwachsene, klinisch gesunde Versuchspferde zur Verfügung. Die Versuchsdurchführung erfolgte in 3 Phasen. Vor Behandlungsbeginn (Tag 0) wurden von jedem Pferd die Kontrolldaten erfasst. Die Applikation der Dexamethasonformulierung erfolgte über einen Zeitraum von 10 Tagen. 2 mal täglich wurden 50 g einer 0,017 %igen Dexamethasonemulsion auf eine definierte Hautfläche (30 x 50 cm) aufgetragen. Die Blutentnahmen zur Gewinnung der Proben erfolgten am 2., 6., 8., und 10. Tag der Behandlung. Die Nachbehandlungsphase erstreckte sich über einen Zeitraum von 20 Tagen ohne die Dexamethasonanwendung. Hier erfolgte die Probengewinnung an den Tagen 3, 7, 11, 14 und 20 nach Absetzen der Behandlung. Aus den gewonnenen Plasmaproben wurden die Konzentrationen von Cortisol, Insulin, T3 und T4 mittels Radioimmunoassay bestimmt, sowie die ACTH-Konzentrationen mittels Chemilumineszenz-Enzymimmunometrischem Assay. Darüber hinaus wurden die hämatologischen und blutchemischen Parameter gemessen. Die Funktion des negativen Feetback-Mechanismus der Hypothalamus-Hypophysen-Nebennierenrinden-Achse wurde mittels eines ACTH-Stimulationstests überprüft. Während der Behandlung konnte eine ausgeprägte Suppression der Nebennierenrindenfunktion, gekennzeichnet durch die signifkante Abnahme der basalen Cortisolkonzentration, auf weniger als 10 % der Ausgangswerte vor der Behandlung gemessen werden. Auch der ACTH-Stimulationstest am 8. Behandlungstag zeigte einen signifikant geringeren Anstieg des Kortisolspiegels (< 50 %) als vor der Behandlung. Weiterhin kam es während der dermalen Verabreichung von Dexamethason zu einer progressiven, signifikanten Zunahme des Serumglucosespiegels bis um das 1,5 fache des Kontrollwertes. Parallel dazu stieg der Plasmainsulinspiegel um das 3-fache des Ausgangswertes vor Behandlungsbeginn. Die Plasmakonzentration von T3 zeigte einen leichten behandlungsbedingten Abfall, wohingegen der Plasma-T4-Spiegel einen deutlichen Rückgang auf 50 % des Ausgangswertes zeigte. Die endokrinologischen Veränderungen waren nach Absetzen der Behandlung alle reversibel. Weiterhin kam es zu einer signifikanten Reduktion der eosinophilen Granulozyten und der Lymphozyten, während die Zahl der Neutrophilen zunahm. Plasmakonzentrationen von Dexamethason konnten mit einem Maximalwert am 8. Tag der Behandlung (1542,10 ± 567 pg/ml) gemessen werden. Diese Ergebnisse belegen, dass bei der dermalen Applikation von Dexamethason eine perkutane Wirkstoffresorption in einem Umfang stattfindet, dass die typischen systemischen Glucocorticoidwirkungen auftreten. Es kann somit auch davon ausgegangen werden, dass die topische Verabreichung schwach wirksamer Glucocorticoidformulierungen eine gewisse Dopingrelevanz besitzt.

La sécurité d’attachement joue un rôle significatif dans la gestion du stress. En effet, elle permet à l’enfant de se réguler, tant sur le plan comportemental, émotionnel que physiologique. Le présent mémoire, qui s’inscrit dans une optique de valorisation des données de recherche, vise à investiguer, d’un point de vue longitudinal, le lien entre la sécurité d’attachement et la synchronisation physiologique des mécanismes de stress chez les dyades mère-enfant. En étudiant la réactivité de l’axe hypothalamo-pituito-surrénalien (HPS) qui régule le cortisol, souvent désigné comme l’hormone du stress, cette étude cherche à comprendre les mécanismes d’harmonisation physiologique de la réponse de stress chez les dyades. Les données qui ont servi à ce projet de mémoire proviennent d’une étude longitudinale de 1995 qui portait sur des mères adolescentes. Bien que les résultats des analyses corrélationnelles ne permettent pas d’identifier des différences significatives entre les différents types d’attachement, les résultats des analyses de variances mixtes à mesures répétées suggèrent que chez les dyades mères-enfants, l’harmonisation du cortisol salivaire se développerait de façon significative entre le 9e et 15e mois, et ce, indépendamment du type d’attachement de l’enfant. Ces résultats suggèrent que, dans les contextes de réactivité au stress, l’harmonisation de l’axe HPS des dyades mères-enfants serait un mécanisme physiologique normatif qui se développe à travers le temps. / Attachment security plays a significant role in stress management. Indeed, it allows the child to regulate his behavior, emotions and physiology. The present dissertation, which is part of a research data valuation approach, aims to investigate, from a longitudinal point of view, the link between attachment security and the physiological synchronization of stress mechanisms in mother-child dyads. By studying the reactivity of the hypothalamo-pituitary-adrenal (HPA) axis that regulates cortisol, often referred to as the stress hormone, this study seeks to understand the mechanisms of physiological attunement of the stress response in dyads. The data for this dissertation project came from a 1995 longitudinal study of adolescent mothers. Although the results of the correlational analyses did not identify significant differences between the different types of attachment, the results of the repeated measures analysis of variance using mixed models, suggest that within mother-child dyads, the attunement of salivary cortisol would develop significantly between the 9th and 15th month of age, independently of the child's type of attachment. These results suggest that, in contexts of stress reactivity, the attunement of the HPS axis of mother-infant dyads would be a normative physiological mechanism that develops over time.

Introduction L’évolution à long terme de la maladie de Hirschsprung (HSCR) est souvent associée à des complications et à un dysfonctionnement de l’intestin, source de conséquences importantes sur la qualité de vie (QdV). L’objectif principal de cette étude est, dans une cohorte québécoise de HSCR, d’étudier la QdV en utilisant un outil spécifique et d’en déterminer les facteurs prédictifs. Méthodes Étude prospective de cohorte et cas-témoins. Les questionnaires 'HAQL' (QdV spécifique de HSCR), 'PedsQL’ (QdV générale), sur le stress et sur la situation sociale ont été administrés, ainsi qu’un journal des selles. Le contenu en cortisol des cheveux (CCC) (mesure du stress chronique) a été quantifié par dosage immuno-enzymatique (ELISA). Résultats 72 patients (72% garçons) et 117 contrôles (65% garçons) ont été analysés. L'âge médian [IQR1-IQR3] à l'inclusion était de 12,1 ans [8-17,5] et 12,6 ans [10,2-15,1] respectivement. La QdV liée à la santé globale était comparable entre les patients et les contrôles. Parmi les patients, la QdV spécifique à la HSCR mesurée par le HAQL était inférieure chez les enfants de 8 à11 ans par rapport aux adolescents de 12 à 16 ans (valeurs moyenne 539,3±66,5/700 vs. 622,6± 54,6/700; p=0,002). La dimension ‘Continence fécale pendant la journée’ était la plus affectée chez les patients âgés de 8 à 11 ans (valeur moyenne 52,6±25,3 sur 100). Chez les patients 12 à 16 ans, la dimension la plus affectée était le ‘Fonctionnement physique’. La prévalence de l'incontinence fécale mesurée chez les patients était de 85% chez les enfants, de 40% chez les adolescents et de 12% chez les adultes. Une association significative entre incontinence fécale et jeune âge était vu (p=<0,0001). Aucune association n'a été démontrée entre incontinence fécale et stress chronique (HCC, événements stressants) ou situation sociale chez les patients. Conclusion L’étude de la QdV par un outil spécifique de la HSCR est nécessaire pour une évaluation adéquate de l’état psychosocial dans cette population qui est à risque d’un dysfonctionnement de l’intestin à long terme. / Introduction Multimorbidity and bowel dysfunction are affecting patients with Hirschsprung disease (HSCR) on long-term follow-up, having an important impact on quality of life (QoL). The primary aim of this study is to evaluate the disease-specific QoL with determination of its predictive factors in a French-Canadian cohort of HSCR patients. Methods Prospective cohort and case-control study. The questionnaires ‘HAQL’ (disease-specific QoL questionnaire), 'PedsQL’ (global health related QoL), ‘Stressful life events’, a questionnaire about the socio-economic state and a stool diary were requested to fill in. Hair cortisol concentration (HCC) (measure of chronic stress) was measured using an enzyme-linked immunosorbent assay kit (ELISA). Results 72 patients (72% males) and 117 controls (65% males) were analyzed. Median [IQR1, IQR3] age at study inclusion was 12.1 years [8,17.5] in patients and 12.6 years [10.2,15.1] in controls. General health related QoL was comparable between patients and controls. In the patient’s group, children 8 to 11 years reported lower disease-specific QoL than adolescents (12 to 16 years) (mean scores 539.3±66.5/700 vs. 622.6±54.6/700; p=0.002). The dimension ‘Fecal continence during daytime’ was the most affected one in children (mean score 52.6± 25.3/100) and the dimension ‘Physical functioning’ was the most affected one in adolescents. Prevalence of fecal incontinence/soiling in the patient’s group was 85% in children, 40% in adolescents and 12% in adults. Younger age was associated with a higher prevalence of fecal incontinence (p=<0,0001). No association was seen between presence of fecal soiling/incontinence and chronic stress (HCC, Stressful live events) or social situation. Conclusion Disease-specific QoL investigation is mandatory in HSCR patients, to encounter and evaluate adequately psychosocial problems related to long term bowel dysfunction.

No description available.

Transdisciplinary research in general, and stress research in particular, requires an efficient integration of methodological knowledge of all involved academic disciplines, in order to obtain conclusions of incremental value about the investigated constructs. From a psychologist’s point of view, biochemistry and quantitative neuroendocrinology are of particular importance for the investigation of endocrine stress systems (i.e., the HPA axis, and the SNS). Despite of their fundamental role for the adequate assessment of endocrine activity, both topics are rarely covered by conventional psychological curriculae. Consequently, the transfer of the respective knowledge has to rely on other, less efficient channels of scientific exchange. The present thesis sets out to contribute to this exchange, by highlighting methodological issues that are repeatedly encountered in research on stress-related endocrine activity, and providing solutions to these issues. As outlined within this thesis, modern stress research tends to fall short of an adequate quantification of the kinetics and dynamics of bioactive cortisol. Cortisol has gained considerable popularity during the last decades, as its bioactive fraction is supposed to be reliably determinable from saliva and is therefore the most conveniently obtainable marker of HPA activity. However, a substantial fraction of salivary cortisol is metabolized to its inactivated form cortisone by the enzyme 11β-HSD2 in the parotid glands, which is likely to restrict its utility. Although the commonly used antibody-based quantification methods (i.e. immunoassays) might “involuntarily” qualify this issue to some degree (due to their inherent cross-reactivity with matrix components that are structurally-related to cortisol; e.g., cortisone), they also cause differential within-immunoassay measurement bias: Salivary cortisone has (as compared to salivary cortisol) a substantially longer half-life, which leads to an overestimation of cortisol levels the more time has passed since the onset of the prior HPA secretory episode, and thus tends to distort any inference on the kinetics of bioactive cortisol. Furthermore, absolute cortisol levels also depend on the between-immunoassay variation of antibodies. Consequently, raw signal comparisons between laboratories and studies, which are favorable as compared to effect comparisons, can hardly be performed. This finding also highlights the need for the long-sought standardization of biochemical measurement procedures. The presumably only way to circumvent both issues is to rely on quantification of ultrafiltrated blood cortisol by mass-spectrometric methods. Being partly related to biochemical considerations with research on HPA activity, a second topic arises concerning the operationalization of the construct itself: In contrast to the simple outcome measures like averaged reaction times, inclined stress researchers can only indirectly infer on the sub-processes being involved in HPA activity from longitudinally sampled hormone concentrations. HPA activity can be quantified either by (a) discrete-time, or by (b) continuous-time models. Although the former is the most popular and more convenient approach (as indicated by the overly frequent encounter of ANOVAs and trapezoidal AUC calculations in the field of psychobiological stress research), most discrete time models form rather data-driven, descriptive approaches to quantify HPA activity, that assume the existence of some endocrine resting-state (i.e., a baseline) at the first sampling point and disregard any mechanistic hormonal change occurring in between all following sampling points. Even if one ignores the fact, that such properties are unlikely to pertain to endocrine systems in general, many generic discrete time models fail to account for the specific structure of endocrine data that results from biochemical hormone measurement, as well as from the dynamics of the investigated system. More precisely speaking, cortisol time series violate homoscedasticity, residual normality, and sphericity, which need to be present in order to enable (mixed effects) GLM-based analyses. Neglecting these prerequisites may lead to inference bias unless counter-measures are taken. Such counter-measures usually involve alteration of the scale of hormone concentrations via transformation techniques. As such, a fourth-root transformation of salivary cortisol (being determined by a widely used, commercially available immunoassay) is shown to yield the optimal tradeoff for generating homoscedasticity and residual normality simultaneously. Although the violation of sphericity could be partly accounted for by several correction techniques, many modern software packages for structural equation modeling (e.g., Mplus, OpenMX, Lavaan) also offer the opportunity to easily specify more appropriate moment structures via path notation and therefore to relax the modeling assumptions of GLM approaches to the analysis of longitudinal hormone data. Proceeding from this reasoning, this thesis illustrates how one can additionally incorporate hypotheses about HPA functioning, and thus model all relevant sub-processes that give rise to HPA kinetics and dynamics. The ALT modeling framework being advocated within this thesis, is shown to serve well for this purpose: ALT modeling can recover HPA activity parameters, which are directly interpretable within a physiological framework, that is, distinct growth factors representing the amount of secreted cortisol and velocity of cortisol elimination can serve to interpret HPA reactivity and regulation in a more unambiguous way, as compared to GLM effect measures. For illustration of these advantages on a content level, cortisol elimination after stress induction was found to be elevated as compared to its known pharmacokinetics. While the mechanism behind this effect requires further investigation, its detection would obviously have been more difficult upon application of conventional GLM methods. Further extension of the ALT framework allowed to address a methodological question, which had previously been dealt with by a mere rule of thumb; what’s the optimal threshold criterion, that enables a convenient but comparably accurate classification of individuals whose HPA axis is or is not activated upon encountering a stressful situation? While a rather arbitrarily chosen baseline-to-peak threshold of 2.5 nmol/L was commonly used to identify episodes of secretory HPA activity in time series of salivary cortisol concentrations, a reanalysis of a TSST meta- dataset by means of ALT mixture modeling suggested that this 2.5 nmol/L criterion is overly conservative with modern biochemical measurement tools and should be lowered according to the precision of the utilized assay (i.e., 1.5 nmol/L). In sum, parametric ALT modeling of endocrine activity can provide a convenient alternative to the commonly utilized GLM-based approaches that enables the inference on and quantification of distinct HPA components on a theoretical foundation, and thus to bridge the gap between discrete- and continuous-time modeling frameworks. The implementation of the outlined modeling approaches by the respective statistical syntaxes and practical guidelines being derived from the comparison of cortisol assays mentioned above, are provided in the appendix of the present thesis, which will hopefully help stress researchers to directly quantify the construct they actually intend to assess.:1. Introduction 2. The hypothalamus-pituitary-adrenal (HPA) axis 3. Induction and quantification of HPA activity 4. The pitfalls of SCC measurement 5. Creating normality and homoscedasticity: GLM-based analyses 6. Relaxing sphericity: moment structure analyses 7. General conclusion