Study of endothelial dysfunction and vascular inflammation in sleep apnea, obesity and aged humans

Obstructive sleep apnea [OSA] has been associated with cardiovascular complications. The overnight repetitive hypoxia represents a form of oxidative stress in the vasculature which may activate the oxidant-sensitive, proinflammatory transcription factor nuclear factor kjB [NF-kjB], affecting endothelial function and atherosclerosis. We investigated whether the endothelial alterations attributed to OSA rather than to other confounding factors. Also, the production of inflammatory cytokine nuclear factor-kappa beta [NFKbeta] was investigated as the molecular mechanism involved in vascular endothelial dysfunction with OSA. Sixty subjects underwent attended nocturnal polysomnography were grouped by apnea hypopnea index: control [AHI<5/h] and OSA cases [AHI>5/h] the cases were further classified according to age and BMI into subgroup IIA: OSA, non-obese, middle age [35-52 y], subgroup IIB: OSA, non-obese, older age group [55-68 y], subgroup IIIA: OSA, obese, middle age group [35-52 y] and subgroup IIIB: OSA, obese, older age group [55-68 y]. A morning venous blood sample was obtained. Neutrophils were isolated, and NF-kjB activity was determined. Plasma sVCAM-1 was assayed by enzyme-linked immunosorbent assay and flow-mediated dilation [FMD] was performed. NF-jB activation and plasma level of sVCAM-1 were significantly increased in OSA patients as compared to the control group and there was no significant difference between the obese and non-obese cases also no significant difference between the middle and old age cases. The degree of NF-kjB activation was positively correlated with indices of apnea severity[r = 0.938; p< 0.001]. FMD was significantly decreased in OSA patients as compared to the control group. These findings suggested that OSA is an independent risk factor for cardiovascular morbidity also that OSA leads to NF-kjB activation, which may constitute an important pathway linking OSA with systemic inflammation and cardiovascular disease

fluoride-release versus non fluoride-release bonding agents

The purpose of this investigation was to compare the shear bond strength of a fluoride-release, one-component system, bonding agent [Syntac Sprint] with that of a non fluoride-release, one component [Exite] and two-component system [Scotch Bond Multi-Purpose] bonding agents. One hundred and twenty caries free unrestored human teeth were selected for the study. The teeth were mounted in an acrylic resin holder with the buccal surface up. Wet grinding was performed until flat enamel or superficial dentine area of at least 4 mm in diameter was exposed. Each bonding agent was applied to the exposed enamel according to the manufacturer's instructions or to the dentine under three different conditions [according to the manufacturer's instructions, in two successive layers and without dentine conditioning]. Immediately, after application and curing of the bonding agents, the composite part of the specimen [Tetric Ceram HP]was build up. The specimens were loaded to fracture in Lloyed Universal Testing Machine. Mean shear bond strength was calculated for each bonding condition. The data were analyzed and compared using ANOVA and LSD statistical test. After debonding, the specimens were examined using stereomicroscope and scanning electron microscope. The results showed that mean shear bond strength of Syntac Sprint to enamel and dentin were adequate to counteract the reported polymerization shrinkage of composite resin. Application of any of the three bonding agents to dentin in two successive layers has no significant effect on increasing bond strength. All adhesives showed adhesive and mixed adhesive mode of failure in all conditions except in non conditioning dentin condition

Study of the effects of streptozotocin-induced diabetes mellitus on serum calcium, parathyroid hormone and creatinine clearance in rats

The acute effects of streptozotocin [STZ]-induced diabetes mellitus on serum calcium, parathyroid hormone [PTH] and creatinine clearance were studied in 20 experimental rats compared with 10 normal controls. The results showed significant hypocalcemia, hyperparathyroidism, hypercalciuria and decreased creatinine clearance