Motor coordination among Greek children: from assessment to intervention

A Thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of PhilosophyBackground: Developmental Coordination Disorder (DCD) describes children with a difficulty to acquire age-specific motor skills. Although there is a significant body of literature addressing developmental and cognitive issues in children with DCD, few studies have actually examined the associations between DCD, physical activity and physical fitness. Therefore, the aim of the present research work was to assess these associations in a series of four successive studies which were set: a) (study 1) to estimate DCD prevalence rates in Greek children and investigate whether these children exhibit different obesity and cardiorespiratory fitness levels than an overseas sample, b) (study 2) to provide evidence on the association between DCD and physical fitness levels, c) (study 3) examine whether a motor skills and exercise training intervention programme affects motor proficiency in a cohort of elementary school children with and without DCD, and d) (study 4) to test the hypothesis that DCD is associated with CVD risk, identify modes of physical activity that mediate such an association and to evaluate the CSAPPA scale as a potential tool for identifying Greek children for DCD. Methods: The total of 574 Greek (Age: 11.46 ± 1.54 years; BMI: 19.96 ± 3.53) children were assessed for anthropometry, physical fitness (flexibility, hand strength, leg explosive power, speed and cardiorespiratory fitness), motor competence (i.e., short form of the Bruininks-Oseretsky Test of Motor Profiency- BOTMP-sf) and subjected to two self assessments for: i) perception of adequacy for physical activity (CSAPPA scale), and ii) children’s participation in physical activity (Participation Questionnaire - PQ). Results: Study 1: Greek children demonstrated significantly higher DCD prevalence rates (p<0.05), higher body fat (p<0.05) and were inferior in both cardiorespiratory fitness (p<0.05) and motor competence (p<0.05) compared to an overseas sample. Study 2: Greek children with DCD demonstrated significantly higher BMI values (p<0.01) and lower leg explosive power (p<0.01), speed (p<0.01) and hand strength (p<0.01) than those without DCD. Study 3: Results showed a significant main effect of time [F(14, 115) = 3.79, p< 0.001; η2 = 0.32] for motor competence (p<0.001) between children with and without DCD. Significant main effects of group (i.e intervention and control groups) [F(42, 351) = 4.01, p< 0.001; η2 = 0.33] were observed for BMI (p<0.01), motor competence (p<0.01), cardiorespiratory fitness (p<0.01), hand strength (p<0.05), leg explosive power (p<0.05), speed (p<0.01), and free time play activities (p<0.05). Study 4: Chi-square comparisons and ANOVA, revealed significantly increased body mass (p<0.05), BMI (p<0.05) and inactivity (p<0.05), as well as significantly decreased cardiorespiratory fitness (p<0.05), motor competence (p<0.05), CSAPPA indices, and participation in free play (p<0.05) in children with DCD. Furthermore, BMI and cardiorespiratory fitness were significantly associated with motor competence (p<0.05) with inactivity as the mediating factor (p<0.05). ROC curve analyses for CSAPPA indicated an optimal cut-off at 62 points. Conclusions: 1) the relatively high DCD and obesity prevalence rates together with the low cardiorespiratory fitness suggest greater health risk for Greek children with the studied condition, 2) children with DCD tend to perform worse in selected physical fitness parameters compared to their normal peers, 3) motor skills and exercise training interventions for children with DCD may improve health and skills related fitness, and 4) inactivity mediates the relationship between DCD and CVD risk in children with DCD. Finally, the CSAPPA scale may serve as a practical and a cost-effective proxy assessment for identifying Greek children with DCD, however as this is not a standardised test for use with children, its use should be treated with caution until further validation work

Peripheral Mononuclear Cell Resistin mRNA Expression Is Increased in Type 2 Diabetic Women

Resistin has been shown to cause insulin resistance and to impair glucose tolerance in rodents, but in humans its physiological role still remains elusive. The aim of this study was to examine whether resistin mRNA expression in human peripheral mononuclear cells (PBMCs) and its corresponding plasma levels are altered in type 2 diabetes. Resistin mRNA levels were easily detectable in human PBMC, and found to be higher in DM2 compared to healthy women (P = .05). Similarly, mononuclear mRNA levels of the proinflammatory cytokines IL-1β, TNF-α, and IL-6 were all significantly higher in DM2 compared to control women (P < .001). The corresponding plasma resistin levels were slightly, but not significantly, increased in DM2 women (P = .051), and overall, they correlated significantly with BMI (r = 0.406, P = .010) and waist circumference (r = 0.516, P = .003), but not with fasting insulin levels or HOMA-IR. Resistin mRNA expression is increased in PBMC from DM2 women, together with increased expression of the inflammatory cytokines IL-1β, TNF-α, and IL-6, independent of obesity. These results suggest that resistin and cytokines might contribute to the low-grade inflammation and the increased atherogenic risk observed in these patients

Motor coordination among Greek children : from assessment to intervention

Background: Developmental Coordination Disorder (DCD) describes children with a difficulty to acquire age-specific motor skills. Although there is a significant body of literature addressing developmental and cognitive issues in children with DCD, few studies have actually examined the associations between DCD, physical activity and physical fitness. Therefore, the aim of the present research work was to assess these associations in a series of four successive studies which were set: a) (study 1) to estimate DCD prevalence rates in Greek children and investigate whether these children exhibit different obesity and cardiorespiratory fitness levels than an overseas sample, b) (study 2) to provide evidence on the association between DCD and physical fitness levels, c) (study 3) examine whether a motor skills and exercise training intervention programme affects motor proficiency in a cohort of elementary school children with and without DCD, and d) (study 4) to test the hypothesis that DCD is associated with CVD risk, identify modes of physical activity that mediate such an association and to evaluate the CSAPPA scale as a potential tool for identifying Greek children for DCD. Methods: The total of 574 Greek (Age: 11.46 ± 1.54 years; BMI: 19.96 ± 3.53) children were assessed for anthropometry, physical fitness (flexibility, hand strength, leg explosive power, speed and cardiorespiratory fitness), motor competence (i.e., short form of the Bruininks-Oseretsky Test of Motor Profiency- BOTMP-sf) and subjected to two self assessments for: i) perception of adequacy for physical activity (CSAPPA scale), and ii) children’s participation in physical activity (Participation Questionnaire - PQ). Results: Study 1: Greek children demonstrated significantly higher DCD prevalence rates (p<0.05), higher body fat (p<0.05) and were inferior in both cardiorespiratory fitness (p<0.05) and motor competence (p<0.05) compared to an overseas sample. Study 2: Greek children with DCD demonstrated significantly higher BMI values (p<0.01) and lower leg explosive power (p<0.01), speed (p<0.01) and hand strength (p<0.01) than those without DCD. Study 3: Results showed a significant main effect of time [F(14, 115) = 3.79, p< 0.001; η2 = 0.32] for motor competence (p<0.001) between children with and without DCD. Significant main effects of group (i.e intervention and control groups) [F(42, 351) = 4.01, p< 0.001; η2 = 0.33] were observed for BMI (p<0.01), motor competence (p<0.01), cardiorespiratory fitness (p<0.01), hand strength (p<0.05), leg explosive power (p<0.05), speed (p<0.01), and free time play activities (p<0.05). Study 4: Chi-square comparisons and ANOVA, revealed significantly increased body mass (p<0.05), BMI (p<0.05) and inactivity (p<0.05), as well as significantly decreased cardiorespiratory fitness (p<0.05), motor competence (p<0.05), CSAPPA indices, and participation in free play (p<0.05) in children with DCD. Furthermore, BMI and cardiorespiratory fitness were significantly associated with motor competence (p<0.05) with inactivity as the mediating factor (p<0.05). ROC curve analyses for CSAPPA indicated an optimal cut-off at 62 points. Conclusions: 1) the relatively high DCD and obesity prevalence rates together with the low cardiorespiratory fitness suggest greater health risk for Greek children with the studied condition, 2) children with DCD tend to perform worse in selected physical fitness parameters compared to their normal peers, 3) motor skills and exercise training interventions for children with DCD may improve health and skills related fitness, and 4) inactivity mediates the relationship between DCD and CVD risk in children with DCD. Finally, the CSAPPA scale may serve as a practical and a cost-effective proxy assessment for identifying Greek children with DCD, however as this is not a standardised test for use with children, its use should be treated with caution until further validation work.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Connection between Telomerase Activity in PBMC and Markers of Inflammation and Endothelial Dysfunction in Patients with Metabolic Syndrome

Metabolic syndrome (MS) is a constellation of metabolic derangements associated with vascular endothelial dysfunction and oxidative stress and is widely regarded as an inflammatory condition, accompanied by an increased risk for cardiovascular disease. The present study tried to investigate the implications of telomerase activity with inflammation and impaired endothelial function in patients with metabolic syndrome. Telomerase activity in circulating peripheral blood mononuclear cells (PBMC), TNF-α, IL-6 and ADMA were monitored in 39 patients with MS and 20 age and sex-matched healthy volunteers. Telomerase activity in PBMC, TNF-α, IL-6 and ADMA were all significantly elevated in patients with MS compared to healthy volunteers. PBMC telomerase was negatively correlated with HDL and positively correlated with ADMA, while no association between TNF-α and IL-6 was observed. IL-6 was increasing with increasing systolic pressure both in the patients with MS and in the healthy volunteers, while smoking and diabetes were positively correlated with IL-6 only in the patients' group. In conclusion, in patients with MS characterised by a strong dyslipidemic profile and low diabetes prevalence, significant telomerase activity was detected in circulating PBMC, along with elevated markers of inflammation and endothelial dysfunction. These findings suggest a prolonged activity of inflammatory cells in the studied state of this metabolic disorder that could represent a contributory pathway in the pathogenesis of atherosclerosis

Control of Precursor Maturation and Disposal Is an Early Regulative Mechanism in the Normal Insulin Production of Pancreatic β-Cells

The essential folding and maturation process of proinsulin in β-cells is largely uncharacterized. To analyze this process, we improved approaches to immunoblotting, metabolic labeling, and data analysis used to determine the proportion of monomers and non-monomers and changes in composition of proinsulin in cells. We found the natural occurrence of a large proportion of proinsulin in various non-monomer states, i.e., aggregates, in normal mouse and human β-cells and a striking increase in the proportion of proinsulin non-monomers in Ins2+/Akita mice in response to a mutation (C96Y) in the insulin 2 (Ins2) gene. Proinsulin emerges in monomer and abundant dual-fate non-monomer states during nascent protein synthesis and shows heavy and preferential ATP/redox-sensitive disposal among secretory proteins during early post-translational processes. These findings support the preservation of proinsulin's aggregation-prone nature and low relative folding rate that permits the plentiful production of non-monomer forms with incomplete folding. Thus, in normal mouse/human β-cells, proinsulin's integrated maturation and degradation processes maintain a balance of natively and non-natively folded states, i.e., proinsulin homeostasis (PIHO). Further analysis discovered the high susceptibility of PIHO to cellular energy and calcium changes, endoplasmic reticulum (ER) and reductive/oxidative stress, and insults by thiol reagent and cytokine. These results expose a direct correlation between various extra-/intracellular influences and (a)typical integrations of proinsulin maturation and disposal processes. Overall, our findings demonstrated that the control of precursor maturation and disposal acts as an early regulative mechanism in normal insulin production, and its disorder is crucially linked to β-cell failure and diabetes pathogenesis

Modeling children's development in gross motor coordination reveals key modifiable determinants. An Allometric approach.

Children change their body size, shape and gross motor coordination (GMC) as they grow. Further, GMC is expected to link to changes in children's body size, physical activity (PA) and physical fitness (PF). The objective was to model GMC changes in children followed longitudinally and to investigate associations between these changes and PA and PF levels. A total of 245 children (122 girls) were observed at 6 years of age and followed annually until 9 years. A sequence of allometric models were fitted, i.e.: 1. body mass, stature and PA; 2. addition of four PF tests; 3. addition of four more PF tests. In Model 1, changes in GMC are non-linear, and body mass (-0.60±0.07, p<0.001) and stature (2.91±0.35, p<0.001) parameter estimates were significant suggesting children with a more linear body size/shape showed higher GMC performances. Girls tend to outperform boys across time, and PA was not associated with GMC changes. Model 2 fitted the data better, and the PF tests (handgrip, standing long jump, 50-yard dash and shuttle-run) were significantly linked to GMC change. In Model 3, adding the remaining PF tests did not change the order of any factors importance. The greatest GMC changes were achieved by children whose body size/shape has an ectomorphic dominance across the years. Considering that leaner and physically fitter children tended to be more coordinated, physical education should also focus on PF development in components related to muscular strength, speed, agility and aerobic capacity, along with nutritional education to reduce fat mass