The number of people having diabetes mellitus is increasing worldwide at an alarming rate. An unbalanced diet rich in carbohydrates and saturated fats, obesity and lack of physical activity, are being blamed. The worldwide prevalence of diabetes for all age-groups has been estimated to be 2.8% in 2000 and projected to be 4.4% by the year 2030. The pathogenesis of diabetes, especially the recent epidemic increase in type 2 diabetes, is still far from clear. Endothelial dysfunction, commonly defined as reduced endothelium-dependent relaxation due to reduced availability of the vasodilator mediator nitric oxide (NO), is a hallmark of diabetes mellitus. Methylglyoxal (MG) is a highly reactive dicarbonyl compound mainly formed as an intermediate during glycolysis. MG is also formed to a lesser extent from protein and amino acid metabolism. However, the relative contribution of various metabolic precursors to MG formation is not known. Levels of MG have been found to be elevated in diabetic and hypertensive conditions but it is not known whether MG is the cause or the effect of these pathological conditions. The aim of my project was (i) to quantify the amount of MG and oxidative stress produced from various substrates in cultured A10 vascular smooth muscle cells (VSMCs), (ii) to investigate the acute in vivo effects of a single dose of MG on glucose tolerance in male Sprague-Dawley (SD) rats, (iii) to investigate the effects of MG on endothelial function and (iv) to investigate the effects, and the underlying molecular mechanisms, of chronic administration of MG on glucose homeostasis in male SD rats. The results show that aminoacetone, a protein metabolism intermediate, is the most potent substrate for MG formation on a molar basis, whereas D-glucose and fructose are equipotent. I also established optimum sample preparation protocols for reproducible measurement of MG in biological samples by high performance liquid chromatography (HPLC). In normal SD rats a single acute dose of MG induced glucose intolerance, reduced adipose tissue glucose uptake and impaired the insulin signalling pathway, which was prevented by the MG scavenger and advanced glycation end product (AGE) breaking compound, alagebrium (ALT-711). MG and high glucose (25 mM) induced endothelial dysfunction in rat aortic rings and cultured endothelial cells by reducing endothelial nitric oxide synthase (eNOS) phosphorylation at Ser-1177, activity and NO production. MG and high glucose also increased oxidative stress and further reduced NO availability in rat aortic rings and cultured endothelial cells. Chronic administration of MG in normal SD rats by continuous infusion with a subcutaneously implanted minipump for 28 days (60 mg/kg/day), induced metabolic and biochemical abnormalities of glucose homeostasis and insulin regulation that are characteristic of type II diabetes. In MG treated rats, insulin stimulated glucose uptake in adipose tissue, and glucose stimulated insulin release from freshly isolated pancreas, were significantly reduced as compared to saline treated control rats. At a molecular level, insulin gene transcription was significantly impaired and apoptosis and DNA fragmentation were more prevalent in the pancreas of MG treated rats as compared to untreated control rats. All of these in vivo effects of MG were attenuated by the MG scavenger, alagebrium. Our data strongly indicate that MG is a causative factor in the pathogenesis of endothelial dysfunction and type 2 diabetes mellitus.

Diabetes mellitus is a chronic disease associated with vascular complications. Vascular endothelial dysfunction caused by increased endothelial cell apoptosis contributes to diabetic cardiovascular complications. The glucose metabolic by-product, D-lactate, is elevated in diabetics and it is unknown whether it contributes to endothelial cell apoptosis. We hypothesized that diabetic D-lactate levels induce apoptosis in human vascular endothelial cells (HUV-EC-C). HUV-EC-C were incubated with 0.2 mM D-lactate (DLA) and mRNA expression of PI3K/AKT pathway members (AKT1, Bcl-2, BAD, eNOS, PI3K) were measured using Quantitative RT-PCR. DLA downregulated all genes at 6 and 24 hours, followed by increase in expression after 48 hours except PI3K, which remained below control. To further investigate apoptosis, the Human Apoptosis PCR Array was used and expression of all proapoptotic genes (TNF family members) and antiapoptotic genes (IAP family members) were decreased and increased, respectively, at 24 hours followed by an increase and decrease, respectively, at 48 hours. Caspase activity, measured using the Caspase-Glo® 3/7 Assay after HUV-EC-C exposure to 0.2 mM DLA alone or in combination with 20 mM glucose (GLU) or 5 µM methylglyoxal (MG), was increased after 1, 72, and 96 hours. Furthermore, to know whether DLA (0.2 mM) and DLA (0.2 mM), GLU (20 mM) and MG (5 µM) combined cause changes in cellular energy metabolism, creatine (Cr) and high-energy phosphate substrates (CrP, ATP, ADP, AMP) were quantified using HPLC and no changes were observed. We further measured ROS production in HUV-EC-C treated with 0.06-2 mM DLA alone or 0.2 mM DLA with 5-30 mM GLU or 5-160 μM MG. All DLA concentrations increased ROS production by 160% to 216%. DLA with GLU or MG significantly increased ROS production compared to GLU or MG alone. Lastly, D-lactate dehydrogenase (D-LDH) expression was determined using Quantitative RT-PCR and D-LDH was not detected in HUV-EC-C. In conclusion, DLA altered expression of different pro- and anti-apoptotic genes in HUV-EC-C. Furthermore, exposure of HUV-EC-C to DLA levels typically present in diabetics resulted in time-dependent changes in caspase activity, possibly due to excessive ROS production. Whether these changes eventually lead to endothelial dysfunction in diabetes needs further investigation.

Cardiovascular disease (CVD) is the leading cause of death in the United States. Analysis of vascular reactivity (VR) in response to brachial artery occlusion is used to estimate arterial health and to determine the likelihood of future cardiovascular complications. Development of a sensitive technique to assess VR is fundamental to the field of preventive cardiology. The conventional technique to study VR is by monitoring arterial diameter changes during hyperemia following occlusion using ultrasound based methods. Such measurements require highly qualified technicians and expensive equipment; and are complicated by signal noise introduced by motion and posture among others. It is well known that tissue temperature changes are a direct response to variations in blood flow, and it has been observed in small clinical studies that variations in fingertip temperature during brachial artery occlusion and subsequent hyperemia is a simple surrogate for the measurement of vascular reactivity and endothelial dysfunction. Given the promising nature of thermal monitoring to study VR, this thesis focuses on the analysis of the underlying physics affecting fingertip temperature during vascular occlusion and subsequent hyperemia. I will quantify the contribution of hemodynamic, anatomical and environmental factors over digit temperature changes, which will serve to determine the sensitivity of the digital thermal monitoring (DTM) technique. I have quantified the effect of several contributing factors to fingertip temperature and DTM results. The aims of this thesis focus on: (1) creation of a mathematical model of heat transfer at baseline, during, and after a reactive hyperemia test; and (2) validation of the model and experimental analysis of thermal and flow parameters in healthy volunteers. The proposed project is an innovative study that intends to show and quantify the relationship between VR and digital thermal reactivity, translating mathematical models based on the physics of heat transfer and fluid mechanics to clinical application. The parametric studies performed with the zeroth order model served to separate the contribution of environment and blood flow over the temperature curves measured during brachial artery occlusion. The thermal models developed were able to reproduce the trend of the temperature response observed experimentally at the fingertip.

In clinical trials of drug treatments for women’s sexual dysfunction, placebo responses have often been substantial. Little is known about the nature and time course of symptom reduction with placebo treatment. It is also unknown to what extent placebo responses might be associated with individual characteristics, such as demographic variables, that influence responsiveness to treatment. Finally, it is unknown how sexual behavior during placebo treatment changes and whether changes in sexual behavior account for variability in outcomes. In the present work I investigated potential between-trial, between-person, and within-person variables that might explain variability in response to placebo treatment of sexual dysfunction in women. Study 1 consisted of a systematic review of the clinical trial literature to estimate the magnitude and predictors of placebo response across previous trials. Study 2 was an analysis of a small sample of women who were randomized to receive placebo in a recent clinical trial. These preliminary studies provided evidence of a relatively large clinical response among women randomized to placebo in controlled clinical trials of sexual dysfunction treatments. In addition, I found evidence of a possible effect of psychosocial variables on placebo response. In Study 3, I further tested the nature and correlates of placebo response in a sample of 50 women with sexual arousal and desire problems. These data were drawn from a 12-week double-blind randomized controlled trial in which measurement of symptom severity took place at baseline, 4 weeks, 8 weeks, and 12 weeks, allowing for longitudinal analysis. Change in sexual function during placebo treatment peaked at 4 weeks and remained relatively stable through post-treatment. Furthermore, change in sexual function was clinically meaningful in approximately one-third of the sample. Symptom improvement appeared to be in part a function of increased frequency of satisfying sexual encounters during treatment, although there remained additional variability in outcomes that could not be explained by the available data. The findings are discussed with reference to enhancing both clinical trial design and psychological therapies in the treatment of sexual dysfunction in women. / text

Στην χρόνια νεφρική ανεπάρκεια, η μειωμένη διήθηση του πλάσματος οδηγεί στην αυξημένη συγκέντρωση τοξινών στο αίμα. Αυτό προκαλεί δυσλειτουργία του ενδοθηλίου, η οποία περιλαμβάνει την φλεγμονή, την αθηροσκλήρωση και τελικά την υπέρταση. Στο πλαίσιο της μελέτης της δράσης των μη διηθούμενων τοξινών, χρησιμοποιήθηκε ορός ασθενών πριν και μετά την αιμοκάθαρση. Ως in vitro σύστημα μελέτης, χρησιμοποιήθηκε πρωτογενής καλλιέργεια ενδοθηλιακών κυττάρων από ομφάλια φλέβα ανθρώπου (HUVEC) και ελέγχθηκε η επίδραση ορού πριν και μετά την αιμοκάθαρση, στον πολλαπλασιασμό, την απόπτωση, την μετανάστευση και την «επούλωση πληγών» των κυττάρων αυτών. Επίσης, μελετήθηκε η έκφραση των μεταλλοπρωτεϊνασών MMP-2 και MMP-9 και των αναστολέων τους TIMP-1 και 2 σε επίπεδο mRNA και πρωτεΐνης καθώς και η έκφραση του κολλαγόνου IV και της ελαστίνης. Χρόνο- και δοσο-εξαρτώμενα πειράματα έδειξαν ότι ο μετά-ορός, σε σχέση με τον προ-ορό, επάγει τον πολλαπλασιασμό, την μετανάστευση και την διαδικασία της «επούλωσης πληγών» των ενδοθηλιακών κυττάρων με στατιστικά σημαντικό τρόπο, ενώ βρέθηκε να μειώνει την απόπτωση. Επίσης βρέθηκε ότι ο προ- ορός, σε σχέση με τον μετά- ορό, επάγει με στατιστικά σημαντικό τρόπο, την έκφραση και ενεργότητα των MMP-2 και MMP-9, ενώ καταστέλλει την έκφραση καθώς και τα επίπεδα των αναστολέων TIMP-1 και TIMP-2. Τέλος καταστέλλει την έκφραση των βασικών συστατικών της εξωκυττάριας ύλης, του κολλαγόνου IV και της ελαστίνης. Συμπερασματικά, ο ορός πριν την αιμοκάθαρση φαίνεται να συμμετέχει στην δυσλειτουργία του ενδοθηλίου, καταστέλλοντας τον πολλαπλασιασμό και την μετανάστευση και επάγοντας ταυτόχρονα την απόπτωση των ενδοθηλιακών κυττάρων. Παράλληλα ο προ-ορός καταστρέφει την εξωκυττάρια ύλη των ενδοθηλιακών κυττάρων επάγοντας τις MMP-2 και -9, καταστέλλοντας τους αναστολείς τους TIMP-1 και -2 και μειώνοντας ταυτόχρονα την έκφραση του κολλαγόνου IV και της ελαστίνης. / In chronic renal disease, reduced glomerular filtration results to increased toxin concentration in blood. This leads, among others, to endothelial dysfunction which concludes inflammation, atherosclerosis and finally hypertension. In this study, in order to investigate the effect of non-filtrated toxins, we used pre-haemodialysis and post-haemodialysis serum (control) from end-stage renal patients. As in vitro system of study we used the primary endothelial cell culture from human umbilical vein (HUVEC) and the effect of pre- and post- haemodialysis serum on cell proliferation, migration, apoptosis and wound healing was investigated. In addition, the expression of matrix metalloproteases MMP-2 and MMP-9 and their inhibitors TIMP-1 and TIMP-2 was examined. Time course and dose-response experiments revealed that pre-serum reduces proliferation, migration and wound healing, while induced apoptosis in a statistically significant manner. Pre-, compared to post-haemodialysis serum, induces the expression and activity of MMP-2 and MMP-9, while inhibits the expression of TIMP-1 and TIMP-2. Concluding, uremic toxins lead to endothelial dysfunction, inhibiting cell proliferation, cell migration and inducing apoptosis. In addition, uremic toxins contribute to the degradation of extracellular matrix, inducing MMP-2 and MMP-9 and inhibiting TIMP-1 and TIMP-2.

Σκοπός: 1) Η μελέτη της επίπτωσης της στυτικής δυσλειτουργίας σε ασθενείς με σύνδρομο επικάλυψης ( ΣΑΑΥ και ΧΑΠ ) και η συγκρισή της με την επίπτωση της στυτικής δυσλειτουργίας σε ασθενείς που παρουσίαζαν μόνο ΣΑΑΥ, και 2) η εκτίμηση της βελτίωσης της στυτικής δυσλειτουργίας (ED) σε άνδρες με σύνδρομο επικάλυψης (αποφρακτική άπνοια του ύπνου και χρόνια αποφρακτική πνευμονοπάθεια) υπό θεραπεία με cPAP (συνεχής θετική πίεση αεραγωγών) και βρογχοδιασταλτικά. Υλικό και μέθοδος : Μελετήθηκαν 48 άνδρες με μέσο όρο ηλικίας τα 52.8 + 10 χρόνια με αποφρακτική άπνοια του ύπνου (ΣΑΑΥ) και χρόνια αποφρακτική πνευμονοπάθεια (ΧΑΠ) και παράλληλα στυτική δυσλειτουργία ED. Επίσης 30 άνδρες με στυτική δυσλειτουργία και ΣΑΑΥ χωρίς αποφρακτική νόσο. Έλαβαν την κατάλληλη θεραπεία για αποφρακτική πνευμονοπάθεια (cPAP και βρογχοδιασταλτικά) για 6 μήνες και έπειτα το επίπεδο της στυτικής λειτουργίας (EF) επανεκτιμήθηκε. Η ED θεωρήθηκε ότι βελτιώθηκε εάν ο βαθμός βελτίωσης (score) αυξήθηκε για τουλάχιστον 5 μονάδες σε σύγκριση με αυτό της βασικής τιμής. Οι καθοριστικοί παράγοντες για βελτίωση της ED επίσης εκτιμήθηκαν, καθώς επίσης και ο βαθμός ικανοποίησης του κάθε ασθενή κατά τη διάρκεια της θεραπείας Αποτελέσματα : Η επίπτωση της ED σε ασθενείς με σύνδρομο επικάλυψης ήταν 81,08%. Η επίπτωση της ED σε ασθενείς πάσχοντες από ΣΑΑΥ και ED ήταν 29,17%. Η ED βελτιώθηκε σε 12 ασθενείς (25%), αλλά μόνο τα 2 /3 αυτών ήταν ικανοποιημένοι με τον βαθμό βελτίωσης μετά από θεραπεία. Η βελτίωση της ED συσχετίστηκε θετικά με την ηλικία, δείκτη άπνοιας / υπόπνοιας και αρνητικά με την διάρκεια της ED. Το score της ED, ο κορεσμός της αιμοσφαιρίνης σε Ο2 κατά τη διάρκεια της νύχτας και το BMI δεν συσχετίστηκαν σημαντικά με το βαθμό βελτίωσης της EF. Συμπεράσματα : 1) Η επίπτωση της ED σε ασθενείς με σύνδρομο επικάλυψης είναι μεγαλύτερη συγκριτικά με αυτή των ασθενών που έπασχαν μόνο από ΣΑΑΥ και συγκριτικά με το γενικό πληθυσμό. 2) Η συνήθης θεραπεία σε ασθενείς με ΣΑΑΥ και ΧΑΠ με βρογχοδιασταλτικά και cPAP έχει θετικά αποτελέσματα στην παράλληλη ED στην μειονότητα των ασθενών αυτών. Από τους άνδρες που βελτιώθηκαν, 1/3 από αυτούς δεν ήταν ικανοποιημένοι με το αποτέλεσμα αυτής της θεραπείας. Διαφορετική θεραπευτική αντιμετώπιση ή συνδυασμός αγωγής θα πρέπει πιθανά να χορηγηθεί στους ασθενείς αυτούς. / Aim: 1) To determine the prevalence of erectile dysfunction in patients with overlap syndrome (obstructive sleep apnea and chronic obstructive pulmonary disease) compared with patients suffered from sleep apnea syndrome and erectile dysfunction and 2)To assess the improvement of concurrent erectile dysfunction (ED) in these patients treated with continuous positive airway pressure (cPAP) and bronchodilators Material and Methods: We evaluated 48 men suffering from OSA, COPD and concurrent ED, and 30 men suffered from OSA and ED. They were treated with conventional therapy for pulmonary obstructive disease (cPAP and bronchodilators) for 6 months and then their erectile function status was reassessed. ED was considered as improved, if ED intensity score increased for at least five points compared to that of baseline. Results: The prevalence of ED in patients with overlap syndrome was 81,08%. The prevalence of ED in men with OSA was 29,17%. ED was improved in 12 patients (25%), but only two thirds of them were satisfied with the grade of improvement after treatment. ED improvement was related positively with age and apnea/hypopnea index and negatively with ED duration. ED intensity score, O2 saturation at night and BMI were not significantly related to the outcome of EF improvement. Conclusions: 1) The prevalence of ED in patients with overlap syndrome was higher compared with the prevalence of ED in men with OSA. 2) Conventional treatment for OSA and COPD, has a positive effect on concurrent ED on the minority of patients. The effect is possibly due to the improvement of respiration during sleep with cPAP and of oxygenation with bronchodilators continuously

Recent studies support the association between metabolic syndrome (MetS), a cluster of cardiovascular risk factors, and diastolic dysfunction. Disproportionate collagen accumulation, particularly cross-linking of collagen, plays a key role in translating interstitial fibrosis into mechanical chamber stiffness and diastolic dysfunction. Characteristic changes in the expression and activity of myocardial lysyl oxidase (LOX), a matrix modifying enzyme that catalyzes cross-linked collagen, are unclear in MetS. We established a diet-induced MetS model to study diastolic dysfunction by treating male C57BL/6 mice a high-fat high-simple carbohydrate (HFHSC) diet for 6 months. Despite blunted gene expression of LOX isoforms, MetS mice demonstrated significant increase in the ratio of protein expression of mature to proenzyme LOX, enhanced LOX activity, and increased cardiac cross-linked collagen compared with controls. This fibrotic response coincided with marked increase in left ventricular end-diastolic pressure and stiffness and impaired diastolic filling pattern. Our data demonstrate that diet-induced MetS alters the remodeling enzyme LOX, thereby increasing the amount of crosslinking and inducing diastolic dysfunction.Furthermore we examined the role of T-lymphocytes in myocardial LOX regulation in diet-induced fibrotic hearts. Female SCID mice which are devoid of functional T-lymphocytes and C57BL/6 mice were treated with HFHSC diet for 12 months. Similar to male C67BL/6, female HFHSC-fed C57BL/6 mice demonstrated significant increase in maturation and catalytic activity of myocardial LOX, cross-linking, ventricular stiffness and diastolic dysfunction. Whereas induction of LOX protein was minimal in SCID mice compared with wild-type counterparts. Correspondingly fibrillar cross-linked collagen formation and diastolic dysfunction were less prominent in SCID mice. Our results suggest a potential role of T-lymphocytes in induction of myocardial stiffness and diastolic dysfunction through modulation of LOX-dependent collagen maturation.Moreover we studied the role of leptin, an adipokine over-produced in MetS with fibrotic effects in non-cardiac tissues, as a key mediator of profibrogenic responses in the heart by administrating leptin to C57BL/6 and leptin-deficient ob/ob mice. With exogenous leptin administration ob/ob mice displayed passive diastolic filling dysfunction that coincided with increase in myocardial collagen compared with ob/ob controls. Our findings suggest profibrotic effects of leptin in the heart, primarily through predominance of collagen synthesis over degradation.

No description available.

Aims: The primary physiotherapeutic aims of the study were to validate a manual physiotherapy evaluation technique in the assessment of cervical biomechanical dysfunction, and to test the effectiveness of a manual physiotherapy treatment technique in the correction of cervical biomechanical dysfunction. The primary educational aims were to test the effectiveness and safety of a therapeutic exercise programme for the correction of biomechanical dysfunction as well as the effectiveness of a neck rehabilitation programme for improving neck muscle strength. Design: A four group experimental design with three pre-test - post-test groups and a control group was used for the investigation. Sample: The subjects were South African schoolboy rugby players between the ages of 15 and 18 years. Groups I and 2 presented with biomechanical dysfunction of their cervical spines, Group 3 had no biomechanical dysfunction of their cervical spines and the players of Group 4, the control group, presented with or without biomechanical dysfunction of their cervical spines. Each group consisted of 25 players. Method: Group I received manual physiotherapy with x-rays before and after treatment. Groups 2 and 3 performed a therapeutic exercise programme, with before and after x-rays, and Group 4 received no intervention between their sets of x-rays. Following the second set of x-rays all the players from Groups I, 2 and 3 performed the neck rehabilitation programme after which a third set of x-rays were taken. Results: The results validated the manual physiotherapy evaluation technique. The manual therapy treatment technique used in the treatment of Group I showed highly significant improvements in cervical biomechanical function. Results for Group 2 following the therapeutic exercise programme showed moderate practically significant improvements in cervical biomechanical dysfunction. The therapeutic exercise programme for the correction of biomechanical dysfunction was found to be very safe with only small significant changes in x-ray measurements (Group 3). The results of the control group showed a negative trend of small statistical significance. A highly significant improvement in cervical circumference as moderate significant improvement in biomechanical function was found following the neck rehabilitation programme. Conclusion: It could therefore be concluded that the manual physiotherapy evaluation technique for motion segment analysis was indeed valid in determining biomechanical dysfunction of the cervical spine. The manual physiotherapy treatment technique as well as the therapeutic exercise programme for the correction of biomechanical dysfunction was found to be effective in the correction of cervical biomechanical dysfunction. It could further be concluded that the therapeutic exercise programme was safe to be performed by players without biomechanical dysfunction. The neck rehabilitation programme was effective in improving cervical circumference as well as cervical biomechanical function. / Thesis (Ph.D. (Education))--North-West University, Potchefstroom Campus, 2005.

Prosocial behaviour is an important building block of children's future social relationships and overall life achievement. The purpose of this study is to increase our knowledge of how various social pathways influence the developmental trajectories of prosocial behaviour in children between the age of 4 and 11. Conceptually, this study rests on the family stress model and its mediating effects, augmented by parental perceptions of neighbourhood social relationships moderating those family pathways. Research is conducted using data from Statistics Canada's National Longitudinal Survey on Children and Youth (NLSCY), and latent growth models (LGM) in four parenting domains: positive interaction, effectiveness, consistency, and rationality. The study supports the hypothesis that family pathways, such as parental depression, family dysfunction, and parenting practices, mediate the relationship between family SES and children's prosocial development. Study findings also demonstrate the important direct effect sizes of all parenting practices on children's prosocial growth. Results suggest that the magnitude of the direct effects of parenting practices on prosocial behaviour, which are non-negligible and positive, are to a great extent negatively affected by the variables defined in the family stress model. Moreover, this research provides new insights about the types of moderation, and the focus of these moderating effects on the family stress model. Thus, findings support the hypothesis that parents' perceptions of neighbourhood cohesion and social support mitigate one or more family pathways more proximal to the child. Overall, this research study contributes in a distinctive manner to the current literature on children's prosocial behaviour development.