Rozprawy doktorskie na temat „Sex-dependent differences”

Calcific aortic valve stenosis (CAVS) is the most common form of heart valve disease and affects about 3% of the population. Its prevalence increases with age, without a causal relation between ageing and CAVS development. To date, CAVS is a slow, progressive, multifactorial disorder considered to be actively driven by several cellular and molecular processes. Its natural history consists of a long clinically silent phase of non-uniform leaflet thickening with or without minimal calcification, known as aortic valve sclerosis (AVSc), without significant obstruction of blood flow, followed by the symptomatic stage, the aortic valve stenosis (AS). Currently, there is no pharmacological therapy preventing CAVS progression nor treating patients with AS. As a result, surgical or percutaneous aortic valve replacement remain the only treatments for severe AS, leaving the pathological molecular and cellular mechanisms unsolved. One of the first trigger of the pathology due to the oxidative stress is the endothelial dysfunction, followed by local inflammation and interstitial cells (VIC) differentiation into myofibroblasts and osteoblasts. Activated valve endothelial cells, undergoing endothelial to mesenchymal transition (EndMT), begin to express mesenchymal adhesion molecules and facilitate monocytes infiltration and local inflammation. These environmental changes induce VIC trans-differentiation into myofibroblast- and osteoblast-like cells. Activated VICs carry out a progressive extracellular matrix (ECM) pathological rearrangement characterized by the activation of fibrosis and calcification processes, which ultimately drive to fibro-calcific deposit formation. In the last years different studies reported sex-related difference in molecular mechanisms in the context of CAVS. In particular, it was shown that men with AS show a higher aortic valve calcium (AVC) load than women. Recently, it has been described that woman aortic valve leaflets were more fibrotic than man ones. Hence, it has been hypothesized that the mechanisms underlying CAVS progression could be different between the two sexes. We confirmed the evidence on sex-related calcium load in a meta-analysis performed on almost three thousand AS patients. Based on our results, AVC load, evaluated by computed tomography, is higher in man AS patients than in woman ones, even normalizing the data for the state of the pathology and for the aortic 9 annulus area. By the CT scan images analysis, we confirmed also the higher prevalence of fibrotic tissue in woman AS patients, than in men. In silico analysis of whole tissue RNA microarray revealed that the cellular composition of the aortic valve was different between men and women with CAVS. In particular, women showed a prevalence of mesenchymal cells, while in men there was a prevalence of inflammatory cells. This finding was in line with the analysis of circulating cytokines: pro inflammatory cytochines such as IL1β, TNFα, INFβ, and INFγ were upregulated in men CAVS patients. Based on these premises, we isolated and characterized VICs from AS patients and performed RNA sequencing to evaluate the differentially expressed molecular mechanisms. Among pathways overactivated in men there was the mitochondrial gene expression and this finding was confirmed by the higher mitochondrial damage in AS VICs from men respect to the one from women. We hypothesized that the mitochondrial damage caused a lower ATP production, therefore we evaluated the effects of a synthetic ATP equivalent, the 2ThioUTP, on the extracellular calcification of VICs from CAVS men. The in vitro 2ThioUTP administration showed indeed lower extracellular calcification of CAVS VICs both in normal and pro-calcifying conditions. All these data, taken together with robust literature evidences, shed light on the influence of sex in the development and progression of CAVS disease. Further studies are needed to better define the sexual dimorphism of this detrimental pathology. The recognition of sex-specific molecular mechanisms, linked to AS onset, may help in the identification of a gender-specific targeted therapy. In this direction, novel pharmacological therapies intended to reduce or even halt CAVS progression could be discovered, providing the basis for a personalized medicine approach in the context of CAVS.

Research during the past decade has highlighted the functional role of perivascular adipose tissue (PVAT) in regulating the contractility of the underlying vascular smooth muscle cell layer. However, the mechanisms underlying these observations are poorly understood. As a sexual dimorphism has been identified in the regulation of vascular tone, the aim of this thesis was to determine whether there are sex differences in PVAT-mediated regulation of the porcine coronary arterial (PCA) tone. In the presence of adherent PVAT, which was stored overnight at 4Co, contractions to the thromboxane mimetic U46619 and endothelin-1 were significantly reduced in PCAs from females, but not PCAs from males. In PCAs pre-contracted with U46619, re-addition of PVAT caused relaxation in PCAs from females, but not PCAs from males. This relaxant response in coronary arteries derived from females was inhibited by a combination of both NO synthase inhibitor (L-NAME) and the cyclooxygenase inhibitor indomethacin. Pre-incubation with an anti-adiponectin antibody abolished the relaxant effects of PVAT, indicating that adiponectin is likely to be the mediator released from the fat. There was no difference in either expression or release of adiponectin from PVAT between sexes. On the other hand, the adiponectin receptor agonist adipoRon produced greater relaxation in PCAs from females compared to PCAs derived from males. No adiponectin receptor 1 expression was detected in PCAs whilst adiponectin receptor 2 and adiponectin binding protein (APPL1) were expressed equally in PCAs from both sexes. Pre-incubation with the hydrogen sulphide enzyme inhibitors 4-propargylglycine (PPG) and 2-(aminooxy)-acetic acid (AOAA) did not reduce the anticontractile responses to PVAT. Cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3MPST) are expressed in PVAT from both sexes equally, with a relatively low activity, whilst no cystathionine γ-lyase (CSE) expression has been identified in PVAT from both sexes. These data indicate a clear sex difference in the regulation of coronary artery tone in response to adiponectin receptor stimulation, which may underlie the anticontractile effects of PVAT in females. Although H2S synthesizing enzymes are expressed in PVAT, they have no functional role in PVAT-induced vasorelaxation. In arteries from both male and female pigs, addition of fresh PVAT caused a contraction, which was partially inhibited by the cyclooxygenase inhibitors indomethacin and flurbiprofen. The PGF2α receptor (FP) antagonist AL8810 attenuated the PVAT-induced contractions in arteries from males, whereas the TXA2 receptor (TP) antagonist GR32191B inhibited the PVAT-induced contractions in arteries from females. Although there was no difference in PGF2α levels in PVAT between females and males, PGF2α produced a larger contraction in arteries from males, correlating with a higher FP receptor expression detected by immunoblotting. In contrast, the release of TXB2 from PVAT from females was greater than the release from males PVAT, but there was no difference in the contraction by the TXA2 agonist U46619. Furthermore, there was no difference in the role of extracellular Ca2+ and Rho kinase pathway (intracellular Ca2+) in the action of U46619, or TP receptor expression in arteries from different sexes. Pre-incubation with the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC), a non-selective NADPH oxidase (Nox) inhibitor (DPI), a selective Nox1 inhibitor (ML171), a selective Nox2 inhibitor Phox-I2 and selective Nox1 and Nox4 inhibitor (GKT137831) significantly reduced PVAT-induced vasoconstriction in PCAs from both females and males. Nox1, Nox2 and Nox4 were expressed equally in PVAT from male and females. However, in PCAs, Nox1 expression was greater in females whilst Nox4 was higher in males. Nox2 was expressed equally in PCAs from different sexes. ML171 and phox-I2 reduced superoxide anion (O2-) production in PVAT and PCAs from both sexes. GKT137831 inhibited H2O2 production in PCAs, but not PVAT, from both sexes. Both U46619 and PGF2α had similar effects on ROS production in that they did not increase O2- production in PVAT while they enhanced O2- production in PCA from females only. Functional studies showed that Nox inhibitors could inhibit the PCAs response to both U46619 and PGF2α in females only. The adipose-derived compound chemerin-9 caused a significantly higher vasoconstriction in PCAs from females in comparison with males PCAs. Similarly, chemerin-9 enhanced Nox activity in females PCAs but not in males PCAs. Chemerin mRNA was expressed in the PVAT, and the chemerin receptor ChemR23 was expressed in PCAs, although there were no sex differences. The anti-chemerin antibody can abolish the PVAT-induced contractions in both sexes. The sexual dimorphism in the contraction to chemerin could be explained by differences in the signalling downstream of the chemerin receptor in PCAs rather than the expression of chemerin or its receptor in PVAT and PCA, respectively. In conclusion, this thesis has demonstrated clear sex differences in the regulation of coronary artery tone by PVAT, with a dual effect of PVAT on the contractility of the PCA. PVAT stored overnight enhanced vasorelaxation in PCAs from females only due to the increased adiponectin activity compared to the males PCAs. In contrast, fresh PVAT augments vasoconstriction in PCAs from both sexes. Prostanoids have an important role in PVAT-induced vasoconstriction in which PGF2α and TXA2 are responsible for vasoconstriction in male and female PCAs, respectively. In addition, chemerin may have a role as a PVAT-derived contractile agent in female PCA only, while Nox-derived ROS regulates PVAT-induced contraction in the PCAs from both sexes. This study highlighted the importance of considering potential sex differences in the responses to PVAT and that sex-specific drug treatment may represent a potential strategy in the treatment of cardiovascular diseases.

Das Ziel der vorliegenden Arbeit war die Identifizierung von Geschlechterunterschieden (GU) in der Expression von miRNAs im späten Stadium der Myokardhypertrophie, sowie der möglichen Rolle von ERbeta bei der Regulierung dieser GU. Unsere früheren Studien identifizierten ERβ als determinierenden Faktor für die beobachteten GU bei Druckbelastung. Unter anderem führte eine Deletion des ERbeta zur Aufhebung der zuvor beobachteten GU auf physiologischer und fibrotischer Ebene, sowie in der Genexpression. In dieser Studie wurden insgesamt 30 miRNAs mit Geschlechter- und/oder Geschlecht*Operation-Interaktionseffekten 9 Wochen nach TAC in WT Mäusen identifiziert. Die gleichen Effekte waren in ERbeta-/- Tieren nicht zu beobachten, teilweise aufgrund einer höheren Expression dieser miRNAs in ERbeta-/- Weibchen als bei den Männchen. Die vorliegende Studie zeigt eine Hemmung vieler miRNAs durch Östrogen (E2) und seine Rezeptoren in weiblichen Kardiomyozyten, welches somit die in vivo-Ergebnisse bestätigt und die protektive Rolle von E2 und ERβ im weiblichen Herzen unterstreicht. Sechs der miRNAs mit GU in WT-, aber nicht in ERbeta-/- Hypertrophie-Modellen wurden als mögliche Fibroseregulatoren identifiziert, da ihnen gemeinsame Inhibitoren des ERK-MAPK-Signalwegs als Zielgene vorhergesagt wurden. Die Expression dieser miRNAs, miR-106a, miR-106b, miR-21, miR-24, miR-27a und miR-27b, war in kardialen Fibroblasten durch E2 geschlechterabhängig reguliert. Zusammengefasst bestätigt diese Arbeit die schützende Rolle von E2 und ERbeta im weiblichen Herzen. E2 und seine Rezeptoren hemmen die Expression vieler miRNAs in weiblichen Kardiomyozyten und kardialen Fibroblasten, sowie in vivo. In männlichen Herzen und kardialen Fibroblasten scheint ERalpha der Hauptakteur zu sein, welcher insbesondere mögliche Fibrose-bezogene miRNAs reguliert. Die verschiedenen Rollen der ERs in weiblichen und männlichen Herzen sind ein bestimmender Faktor der beobachteten GU bei Myokardhypertrophie.
The present study aimed to identify sex-differently expressed miRNAs in a late stage of hypertrophy (9 weeks) and the possible role of ERs in the regulation of these differences. Our previous studies identified ERbeta as an important determinant factor of the observed sex differences in pressure overload, playing different roles in males and females. This report identified a total of 30 miRNAs with sex and/or sex*surgery interaction effect 9 weeks after TAC in WT mice. The same effects were not observed in ERbeta-/- animals partially due to the higher expression of these miRNAs in ERbeta-/- females than in their WT counterparts. This study reveals a repression of a number of miRNAs by estradiol and its receptors alpha and beta in female cardiomyocytes, confirming the in vivo results and accentuating the important protective role of oestrogen and ERbeta in the female heart. Six of the miRNAs with sex differences in WT but not in ERbeta-/- hypertrophy models were found to be possible fibrosis regulators by putatively targeting common ERK/MAPK pathway inhibitors. MiR-106a, miR-106b, miR-21, miR-24, miR-27a and miR-27b were subjected to a different regulation by estradiol in cardiac fibroblasts in a sex-dependent manner. In conclusion, this study reinforces the oestrogen and ERbeta protective roles in the female hearts. Estradiol and ERs repress many miRNAs’ expression in both female cardiomyocytes and cardiac fibroblasts, as well as in vivo. In male hearts and cardiac fibroblasts, ERalpha is apparently the major player, regulating in particular potential fibrosis –related miRNAs. The different roles of ERs in male and female hearts are a determinant factor of the observed sex differences in cardiac hypertrophy.

Background: To determine the role of muscle mass in sex-dependent differences in power output during flywheel resistance training (FRT). Methods: Twenty recreationally active (≥ 2 resistance exercise bouts per week), subjects (10 M, 10 F) completed 2 bouts of resistance exercise using a flywheel resistance training (FRT) device (Exxentric kbox 4 Pro) separated by at least one week. Each session consisted of 3 sets of 4 exercises (squat, bent-over row, Romanian deadlift, and biceps curl) with varying moments of inertia (0.050, 0.075, and 0.100 kg/m2, respectively) in random order. Each set consisted of 5 maximal effort repetitions with 3-minute recovery between sets. Average power, peak concentric and peak eccentric power were recorded and normalized to whole-body skeletal muscle mass (as calculated from bioelectrical impedence analysis). Additionally, linear regression analysis was used to determine the association between muscle mass and highest power output observed among all three inertial loads. Results: Absolute average, peak concentric and peak eccentric power for all lifts was significantly higher for males compared to females except for peak eccentric power for biceps curl which showed no significant difference. After normalizing to skeletal muscle mass, power output remained significantly higher for men in Row average power and peak concentric power as well as average power for biceps curl. A significant main effect of inertial load was noted for both absolute and relative power output for all exercises except for squat average power and peak concentric power. Regression analysis revealed that power output increases linearly with skeletal muscle mass (R2 = 0.37-0.77). Conclusions: Differences in power output between sexes during resistance exercise can largely be explained by differences in muscle mass. Indeed, muscle mass accounts for approximately 37-77% of the variance in power output during FRT depending on the exercise. Increasing inertial load tends to decrease power output during FRT.

Despite the importance of the spike jump in volleyball and the high number of female athletes at high level, movement analyses of the volleyball spike jump were mainly conducted in male players. Potential sex-dependent differences were marginally considered in the scientific literature and practical training. The few studies that tackled this problem can, due to limitations, only hint on the existence of sex differences in essential movement characteristics. Investigations on factors that determine performance in females are also lacking; frequently, performance determinants found in males were assumed to be identical in female players. Consequently, sex-specific training measures to improve technical movement characteristics in the volleyball spike jump are not common. The purpose of this dissertation was 1) to investigate sex-specific differences in movement characteristics, 2) to identify performance determinants in females, and 3) to implement and assess a specific technical training to enhance volleyball spike jump performance in female players. One female and one male team (n1=15, n2=15) competing in the highest Austrian division were recorded via 12 Vicon MX-13 (250 Hz) cameras, two AMTI force plates (2000 Hz), and surface electromyography (2000 Hz) in 5 lower limb muscles. They performed volleyball spike jumps striking a stationary ball and the data was assessed to identify sex differences and performance determinants in females. Based on these findings, a specific six-week training intervention was derived and implemented for female players (n=12). Kinematic and kinetic data were obtained during three measurement sessions with six weeks between the sessions to allow for a comparison between control and intervention phase. Significant (p<.05) sex differences were documented in approach, arm and torso usage, neuromuscular activation pattern, range of motion and acceleration distances, and the strategy to convert horizontal into vertical velocity. Correlation and regression analyses revealed that a majority of these variables affected jump height in females. A subsequent technical-coordinative training intervention that specifically focused on the relevant movement characteristics improved jump height by 11.9% during the competitive season. The intervention resulted in beneficial adaptations in all measured movement characteristics that were not strictly related to strength and power abilities. The sex differences corroborated that technical patterns identified on the basis of a sample that consists of males only cannot be assumed to be identical in females without any further investigation. The second study showed that several characteristics where differences have been found affected spike jump performance in female players. Therefore, they should not be ignored and, instead, addressed in specific training measures. The training intervention study reported positive effects of such approach. The training measure applied in this study showed to effectively enhance female spike jump performance at high level in a short amount of time. However, this training approach requires biomechanical understanding of performance determinants from the coach and specific adaptations to the target group.

Sexually selected ornaments are among the most spectacular traits in nature. Indeed, the extreme costs associated with producing sexual traits seem to play a crucial role in their evolution by enforcing honest levels of advertisement: only males with high levels of acquired resources (or high ‘condition’, as it is known in the literature) can afford to produce extravagant signals, a phenomenon which maintains signal reliability in a constant environment. In my thesis I examine many implications of this condition-dependent model of ornament and preference evolution for variation in age-dependent allocation to sexual signals and other life history traits. In Chapter 1, I review theoretical implications of condition-dependent signalling for life history and sexual selection theory. I note that a universal cost of expenditure in sexual advertisement is metabolic in nature: metabolites used to fund ornament expression are by definition unavailable to other life history traits that compete for a limited resource pool. This universal constraint on expenditure does more than maintain honesty (as noted above), however: the reliance of sexual displays on high levels of nutrient acquisition may help maintain genetic variation in sexual signals that would otherwise be eroded by strong mate choice, and without which the selective basis for good-genes choice would disappear. Three mechanisms in particular probably help to maintain genetic variation in acquisition. 1) Because acquiring resources and converting them efficiently to useful forms depends on the high function of many biochemical pathways, condition is undoubtedly highly polygenic, which slows the erosion of genetic variation under strong directional selection by females (especially in the presence of epistatic interactions). 2) The highly polygenic nature of condition also presents a large target for mutation, which continually restores variation at the loci under selection. 3) The many loci underlying condition may also be particularly sensitive to environmental heterogeneity in time or space. By favouring the most ornate males, females acquire high performing genes for their offspring, regardless of the precise allele combinations that have conferred the ability to acquire resources. Selection on specific alleles is liable to fluctuate over time or space whenever allelic performance is strongly context-specific. I close by noting the considerable challenges in advancing research on sexual selection and life history allocation, including the fact that two key processes central to life history (acquisition and allocation) are latent variables that interact in complexways and are intrinsically difficult to measure empirically. In the remainder of my thesis I conduct a series of experiments involving decorated crickets, Gryllodes sigillatus, which are useful models for studying life history because they enable precise measurement of male reproductive effort. Male G. sigillatus face important allocation decisions owing to the highly polyandrous nature of females, and the substantial costs involved in signalling and mating. Chapter 2 examines sex differences in age-dependent reproductive effort as a function of diet and development stage. I reared outbred crickets using four combinations of diet nutritional quality, and studied the effects of these combinations on male and female reproductive effort (calling effort in males and fecundity in females) and longevity. While I expected males to be more sensitive than females to variation in diet and developmental changes in its quality, I actually observed the opposite: males in all treatments increased calling effort over time, exhibiting consistently positive covariance between calling effort and longevity across treatments. By contrast, the relationships between female reproductive effort and longevity changed dramatically across treatments, and females who lived to intermediate ages had the highest fecundity. Although my results support sex-specific selection on life history allocation over time, a compelling additional explanation for my findings relates to the strategic role of calling for achieving male fitness. In the absence of positive feedback from potential mates, perhaps male allocation to sexual advertisement is careful and only increases gradually as a function of accumulating metabolic resources and increasing risk of intrinsic mortality. Alleles underlying condition are expected to be particularly sensitive to environmental heterogeneity. While this sensitivity may help maintain additive variation in male quality (which is essential for the sustenance of adaptive good-genes mate choice, as noted in Chapter 1), too much environmental sensitivity could also underiii mine the signal value of the male trait. For example, if there are strong genotypeby- environment interactions (GEIs) for sexual advertisement, in a rapidly changing environment females risk favouring a male whose alleles are no longer best suited to current conditions. This problem is particularly pressing for animals like crickets where males exhibit a behaviourally plastic sexual display (such as calling), and so may dynamically adjust signalling effort over time. In Chapter 3, I used inbred lines of decorated crickets to quantify age and diet dependent genetic variation in male signalling. I demonstrate that while genetic correlations across diets were quite strong for morphological traits, correlations between measures of the male sexual trait rapidly approached zero as I increased the distance in time (i.e., across widely spaced ages) or diet (i.e., comparing more dissimilar dietary histories) between samples. While extrapolating from my laboratory experiments to nature is difficult, my findings nevertheless cast doubt on the value of behaviourally dynamic signals (such as cricket calls) for reliably indicating genetic quality in realistically complex environments. In Chapter 4 I used physiological assays to evaluate factors affecting metabolite storage and use over time in decorated crickets. I manipulated the acquisition ability of all males using artificial diets that varied linearly in nutrient quality, and manipulated access to female mates over the course of the second week of adult life. By sacrificing crickets at key stages before and after manipulating the diet and social environment, I was able to estimate changes in stored metabolites, and relate these changes to calling effort and longevity. During the first week of adulthood (in the absence of females), higher diet quality significantly increased calling effort and storage of lipid, glycogen, and carbohydrate (but not protein). The presence of females increased both the probability of calling and the amount of calling during the second week, whereas diet quality only improved calling effort. By the end of the second week, calling effort had decreased, even by high quality males in the presence of females, suggesting a depletion of resources. Furthermore, the loss of condition during week 2 covaried with calling effort during the previous week irrespective of diet. Males who started the second week in high condition lost more glycogen and carbohydrate than rivals; meanwhile, lipid accumulation covaried positively with calling effort during week 2. The contrasting patterns of storage and use for lipids compared to the ‘quick-release’ metabolites (glycogen and carbohydrates) affirms starkly distinct functions for the different storage components, and underlines the importance of specific physiological measures in life history research. Finally, in the general discussion, I attempt to synthesise my thesis’s contributions to the study of life history trade-offs involving behavioural sexual displays.

Multiple interactions between dopamine (DA), glutamate, and nitric oxide (NO) in mesolimbic and corticostriatal circuits suggest that NO may play a critical role in cocaine-induced behavioral and neural plasticity. Clinical and preclinical studies have revealed that females and adolescents display unique vulnerabilities to the behavioral and neurochemical effects of cocaine as a result of sex-dependent and ontogeny-dependent differences in dopaminergic systems. Thus, my research objectives were to investigate the contributions of the neuronal nitric oxide synthase (nNOS) gene, ontogeny, and gender on the rewarding and sensitizing effects of cocaine. I found that nNOS significantly influences the rewarding aspects of cocaine in adolescent mice and adult male mice (i.e., major deficits in several phases of cocaine conditioned place preference (CPP) were detected in nNOS knockout (KO) adolescent mice and nNOS KO adult male mice). However, the contribution of nNOS was sex-dependent as CPP phases were normal in KO adult females. In contrast to CPP, I found a major ontogeny-dependent contribution of nNOS to the sensitizing effects of cocaine. Namely, while nNOS is essential for the development of behavioral sensitization in adult males, this type of behavioral plasticity develops independently of nNOS during adolescence. The contribution of nNOS was once again sex-dependent as behavioral sensitization was normal in adult KO females. Together, this line of investigation has revealed that the NO-signaling pathway has a) a sex-dependent role in the neuroplasticity underlying cocaine CPP and b) a sex-dependent and ontogeny-dependent influence on cocaine-induced behavioral sensitization. Stereological and western blot analysis revealed that a sensitizing regimen of cocaine resulted in an increase in nNOS and tyrosine hydroxylase (TH) immunoreactivity in the dorsal striatum (dST) of adult, but not adolescent, wild-type (WT) male mice. In the absence of nNOS, dopaminergic neurons in the ventral tegmental area (VTA) were severely reduced and cocaine caused a downregulation of dST TH suggesting that nitrergic levels modulate TH. Thus, the finding that nNOS is essential for the development of sensitization in adulthood, but not adolescence, together with the fact that cocaine upregulated nNOS and TH in the dST in adult, but not adolescent mice, strongly suggest that the nitrergic system underlies behavioral sensitization through modulation of the dopaminergic system in adulthood. These findings suggest different approaches in the clinical treatment of drug craving and drug-seeking behavior in adolescent and adult patients.

The topic of badgers in the UK is often a contentious one, dividing opinions and sparking political debate. On one hand, badgers represent an important part of the British ecosystem but on the other a wildlife reservoir of disease implicated in the transmission of bovine tuberculosis (TB) to livestock in the UK. This has prompted strong interest in their population dynamics and epidemiology. Using data from a long-term study of a naturally infected badger population in Woodchester Park, Gloucestershire, this thesis explores a range of capture-mark-recapture (CMR) models to further understand disease and demographic processes. The first section examines long term population dynamics, simultaneously estimating demographic rates alongside their drivers using integrated population models (IPMs). The findings provide new insight into badger demography, highlighting density-dependent mechanisms, vulnerabilities to changing climate and disease prevalence and subsequently how multi-factorial analyses are required to explain fluctuating badger populations. The following sections use multistate models to answer pertinent questions regarding individual disease dynamics, revealing rates of TB infection, progression and disease-induced mortality. A key finding was sex-differences in disease response, with males more susceptible to TB infection. After applying a survival trajectory analysis we suggest sex differences are due to male immune defence deficiencies. A comparative analysis demonstrated similarities between epidemiological processes at Woodchester Park to an unconnected population of badgers from a vaccine study, supporting its continued use as a model population. The final study in this thesis constructs an IPM to estimate disease and population dynamics and in doing so uncovers disease-state recruitment allocation rates, demographic and population estimates of badgers in varying health-states and predicts future dynamics. This model aims to encapsulate the more commonly held notion of populations as dynamic entities with numerous co-occurring processes, opening up avenues for future analyses within both the badger-TB system and possible extensions to other wildlife reservoir populations.

La plasticité à court-terme des synapses GABAergiques dans la lamina II de la moelle épinière est essentielle pour le traitement des messages nociceptifs. Cette plasticité diffère selon le type de neurone postsynaptique, excitateur ou inhibiteur. Nos résultats indiquent une modulation liée au sexe de la transmission synaptique GABAergique, et donc une modification de la plasticité des synapses GABAergiques, notamment en réponse à une inflammation périphérique aiguë. Ces modulations soulignent l'importance de la balance entre l’inhibition et l’excitation dans le traitement des informations nociceptives. Ces observations suggèrent que les mécanismes de modulation de la transmission synaptique GABAergique pourraient expliquer les disparités de sensibilité mécanique et thermique au chaud selon le sexe. Nos travaux enrichissement la compréhension des mécanismes neurobiologiques de la nociception, en tenant compte des différences liées au sexe encore trop souvent négligées
The short-term plasticity of GABAergic synapses in the lamina II of the spinal cord is essential for processing nociceptive information. This plasticity varies depending on the type of postsynaptic neuron, whether excitatory or inhibitory. Our findings indicate a sex-specific modulation of GABAergic synaptic transmission, particularly in response to acute peripheral inflammation. These observations highlight the importance of maintaining a balance between inhibition and excitation in processing nociceptive information. They also suggest that mechanisms regulating GABAergic synaptic transmission may explain differences in mechanical and thermal sensitivity between males and females.Our work enhances understanding of the neurobiological mechanisms of nociception, considering often overlooked sex-related differences

The problem of this study was to discover the relationship between field-independent and field-dependent cognitive styles and social behaviors during free-play of preschool children in a school setting. This study also compared the field-independent and field-dependent cognitive styles and social behaviors during free-play between age-groups and sex-groups. Thirty-six children from a university child development laboratory were subjects. They were selected from a 3-year-old classroom and a 4-year-old classroom. The research instrument, the Preschool Embedded Figures Test, was utilized to measure field-independent and field-dependent cognitive styles. The children's social behaviors were observed during free-play for four consecutive weeks. The nine categories of social behavior were solitary, parallel, and group play; .unoccupied, onlooker, transitional, and aggressive behaviors; and conversations with teachers and conversations with peers. Correlations between field-independent and field-dependent cognitive styles and social behaviors indicated that field-independence/field-dependence was related to social orientations in preschool children and also related to the choice of play activity. Field-dependent children tended to engage in conversations with teachers more often than field-independent children. Four-year-old children who were field-independent tended to spend more time in solitary play than 4-year-old children who were field-dependent. Four-year-old boys who were field-independent tended to play more often in the manipulative learning center than 4-year-old boys who were field-dependent. There were significant differences between age-groups but not significant differences between sex-groups in field-independence/field-dependence. Some social behaviors were significantly different between age-groups and sex-groups. Three-year-old children participated significantly more in physically aggressive behavior and less in conversations with peers than 4-year-old children. Boys engaged significantly more in aggressive behavior than girls.

Background and Aims: Sex differences have been observed in several cardiovascular diseases, in terms of mortality and morbidity. Female patients experience worse clinical outcomes than their male counterparts. Although multiple mechanisms may be involved, sex differences in vascular reactivity of large and small blood vessels have not been investigated. This thesis aims to assess sex-dependent difference in vasoconstrictor responses of human vessels isolated from a variety of vascular beds from older patients (mean age 68 years) with and without existing coronary artery disease. Specific aims include evaluation of :(1a) sex differences in vascular responses of internal mammary artery (IMA) and saphenous vein (SV) segments from male and female patients undergoing CABG and (1b) mechanisms underlying sex dependent vascular responses. (2) sex differences in microvascular reactivity of vessels isolated from mediastinal and peripheral subcutaneous areas in patients with CAD. (3a) sex difference in vascular reactivity of subcutaneous microvessels from patients with no known CAD, undergoing elective non-cardiac surgery. (3b) subcutaneous microvascular reactivity of males and females patients with CAD to those without known CAD. Methods: This thesis used wire myography technique to assess functional changes in vasoconstrictor responses of isolated large conduit and small blood vessels. Concentration-response curves were formed for various vasoconstrictors including phenylephrine, serotonin, endothelin-1 and the thromboxane mimetic, U46619. Western blot analysis was employed to measure the biochemical parameters, including receptor abundance endothelin-1. Summary of major findings: Female IMA segments display hypersensitive responses to serotonergic and α₁-adrenergic receptor stimulation, compared to males. Blocking eNOS and/or cyclooxygenase revealed that prostaglandins account for in the observed α₁-adrenergic mediated sex differences. Biochemical analysis revealed increased density of 5HT2A [2A in subscript] receptors in the female IMA. Similar sex differences were observed in the pericardial microvessels of the same patient cohort, with females showing increased sensitivity to serotonergic and α₁-adrenergic receptor stimulation. Interestingly, no sex differences were observed in the peripheral subcutaneous microvessels of patients with existing CAD. In patients without known CAD, female subcutaneous microvessels were hypersensitive to serotonergic and α₁-adrenergic receptor stimulation, compared to matched males. When compared to subcutaneous microvessels of male and female patients without known CAD, male and female CAD patients exhibited increased sensitivity to a1- adrenergic agonist. Male CAD patients were also hypersensitive to serotonin and the thromboxane A₂ mimetic, U46619, relative to those without known CAD. Conclusions: For the first time, in a population cohort with a mean age of 68 years, female vascular hyper-reactivity in both large graft arteries (IMA) and microvessels has been demonstrated. Female vascular hypersensitivity is consistently seen in response to serotonergic and α₁-adrenergic receptor agonist. In part, this may be due to sex-differences in prostanoid activity. The IMA hyper-reactivity in the group of older women may contribute to their poorer outcomes following CABG and microvascular differences amongst patients without documented cardiovascular disease may pre-dispose them to hypertension.
Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2015

碩士
國立新竹教育大學
教育心理與諮商學系碩士班
98
The purpose of this study was to examine sex differences and field-dependent -independent differences in the performance of sixth grade students’ reading comprehension. The study sampled 251 sixth grade students as subjects, employed the Hidden Figure Test and the Chinese Reading Comprehension Test as instruments, and applied χ2 tests, t-tests, and two-way mixed design ANOVA as data analyses. The major findings of the study are: First, no sex difference was found in the field-dependent-independent. Second, females showed better performances in all aspects of reading comprehension than males. Third, the field-independent students showed better performances in all aspects of reading comprehension than the field-dependent students. Forth, neither the interaction between sex and aspects of reading comprehension, nor the interaction between field-dependent-independent and aspects of reading comprehension was found. In general, students had better performances in low aspects of reading comprehension than in high aspects of reading comprehension.

Males have greater hypertension prevalence and progression than females suggesting sex differences in the underlying mechanisms. This study investigates the intrarenal renin-angiotensin system (RAS) to resolve the hypothesis that sexual dimorphism in the responses of intrarenal angiotensinogen (AGT) and renin synthesized in the collecting ducts (CD renin) exacerbate hypertension in male more than female Sprague-Dawley rats during chronic Angiotensin II infusion (Ang II) (80 ng/min). Additionally, high salt (HS) diet (8% NaCl) was administered to assess sex differences in these RAS components response. Measurements of AGT and CD renin gene expression and urinary excretion showed that AGT message levels were higher in normal salt (NS), HS and Ang II males than females. CD renin expression is lower in female than male rats and responds to HS by increasing in females but is unchanged in the males. Urinary renin excretion is lower in all females than males. Urinary Ang II (uAng II) levels are lower in females than males fed NS or HS diet. Therefore a basal sex difference exists whereby males have higher levels of intrarenal AGT and CD renin. Female rats with Ang II infusion have greater uAngII levels than the Ang II males and the addition of HS diet exacerbates the uAngII levels of males but not female rats. SBP also showed salt sensitivity in Ang II male rats but not females. An Ang II receptor blocker (ARB) was administered to assess sex differences in RAS therapy and the effects of estrogen on AGT and CD renin were assessed in a cohort of ovariectomized (OVX) females. ARB treatments returned SBP to normal in both sexes, but only in females were the proteinuria and increased uAGT prevented. CD renin message and excretion levels were decreased in Ang II OVX rats vs. intact and uAngII was also reduced suggesting that the loss of estrogen did not exacerbate the intrarenal RAS. In summary, decreased levels of AGT and CD renin in female rats suggests a less active intrarenal RAS than in males. Exacerbation of uAGT, proteinuria and uAng II in males by HS diet during Ang II infusion demonstrates augmented salt sensitivity compared to females which would increase the progression of hypertension
acase@tulane.edu

Arctic Cod, Boreogadus saida (Lepechin 1774) occur throughout the circumpolar north at all levels of the water column depending on their life history stage, the time of day, the season, and their activity. Arctic Cod are the most abundant fish species in the Canadian Beaufort Sea (CBS) ecosystem, and are an important link in the flow of energy within the food web. This study examined differences in energy acquisition and usage in Arctic Cod among three depth zones in the CBS (from 15-800m) by examining stomach contents and physiological indicators, taking into account sex, age and body size. Nonparametric comparison analyses found no differences with depth, but support for an ontogenetic shift in diet regarding prey size, a difference in energy content of an average diet between size classes 1 (30-60mm) and 2-4 (2: 60-90mm; 3: 90-120mm; 4: >120mm), and a slight positive relationship between physiological indicators and body size.
October 2016

abstract: The present series of studies examined whether a novel implementation of an intermittent restraint (IR) chronic stress paradigm could be used to investigate hippocampal-dependent spatial ability in both sexes. In experiments 1 and 2, Sprague- Dawley male rats were used to identify the optimal IR parameters to assess spatial ability. For IR, rats were restrained for 2 or 6hrs/day (IR2, IR6, respectively) for five days and then given two days off, a process that was repeated for three weeks and compared to rats restrained for 6hrs/d for each day (DR6) and non-stressed controls (CON). Spatial memory was tested on the radial arm water maze (RAWM), object placement (OP), novel object recognition (NOR) and Y-maze. The results for the first two experiments revealed that IR6, but not IR2, was effective in impairing spatial memory in male rats and that task order impacted performance. In experiment 3, an extended IR paradigm for six weeks was implemented before spatial memory testing commenced in male and female rats (IR- M, IR-F). Unexpectedly, an extended IR paradigm failed to impair spatial memory in either males or females, suggesting that when extended, the IR paradigm may have become predictable. In experiment 4, an unpredictable IR (UIR) paradigm was implemented, in which restraint duration (30 or 60-min) combined with orbital shaking, time of day, and the days off from UIR were varied. UIR impaired spatial memory in males, but not females. Together with other reports, these findings support the interpretation that chronic stress negatively impairs hippocampal-dependent function in males, but not females, and that females appear to be resilient to spatial memory deficits in the face of chronic stress.
Dissertation/Thesis
Masters Thesis Psychology 2019