In vitro biodegradation, cytotoxicity, and biocompatibility of polylactic acid/napier cellulose nanofiber scaffold composites.

This study aimed to evaluate the bioactivities and biocompatibilities of porous polylactic acid (PLA) reinforced with cellulose nanofiber (CNF) scaffolds. The in vitro degradation behaviors of the porous PLA/CNF scaffolds were systematically measured for up to 8 weeks in a phosphate-buffered saline medium at 37 °C. The reinforcement of CNF resisted the biodegradation of the scaffolds. The in vitro cytotoxicity and biocompatibility of the scaffolds were determined using the Beas2B American Type Culture Collection cells. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity and proliferation tests showed that the scaffolds were non-toxic, and epithelial cells grew well on the scaffold after 7 days of culture, whereas the percentage of cell proliferation on the PLA/CNF15 scaffold was the largest, 130 %. A scratch wound-healing assay was performed to evaluate the suitability of the scaffolds for cell migration. The results demonstrated that the scaffolds exhibited good cell migration towards nearly complete wound closure.

Obstructive Sleep Apnea and Ophthalmic Disorders-Clinical Implications.

Sleep is essential for physical, mental and emotional well being. Body systems require sleep of good quality and quantity for their proper functioning. There are several sleep disorders. Obstructive sleep apnea hypopnea syndrome (OSAHS) is one of the most important disorders identified in the last 50 years. The disorder has systemic ill effects by virtue of cyclical hypoxia and sympathetic stimulation. It is a risk factor for the development of hypertension, ischemic heart disease, type 2 diabetes mellitus, stroke and dementia. Retina being the highest oxygen consuming part of the body, is particularly vulnerable to the effects of hypoxia. Several eye disorders have been identified to be associated with OSAHS. In clinical practice Identifying and treating sleep disorders have been rewarding.

In vitro degradation of a 3D porous Pennisetum purpureum/PLA biocomposite scaffold.

The in vitro degradation and mechanical properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA)-based scaffold were investigated. In this study, composite scaffolds with PP to PLA ratios of 0%, 10%, 20%, and 30% were immersed in a PBS solution at 37°C for 40 days. Compression tests were conducted to evaluate the compressive strength and modulus of the scaffolds, according to ASTM F451-95. The compression strength of the scaffolds was found to increase from 1.94 to 9.32MPa, while the compressive modulus increased from 1.73 to 5.25MPa as the fillers' content increased from 0wt% to 30wt%. Moreover, field emission scanning electron microscopy (FESEM) and X-ray diffraction were employed to observe and analyse the microstructure and fibre-matrix interface. Interestingly, the degradation rate was reduced for the PLA/PP20 scaffold, though insignificantly, this could be attributed to the improved mechanical properties and stronger fibre-matrix interface. Microstructure changes after degradation were observed using FESEM. The FESEM results indicated that a strong fibre-matrix interface was formed in the PLA/PP20 scaffold, which reflected the addition of P. purpureum into PLA decreasing the degradation rate compared to in pure PLA scaffolds. The results suggest that the P. purpureum/PLA scaffold degradation rate can be altered and controlled to meet requirements imposed by a given tissue engineering application.

Mechanical, thermal and morphological characterisation of 3D porous Pennisetum purpureum/PLA biocomposites scaffold.

The mechanical, thermal, and morphological properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA) based scaffold were investigated. In this study, a scaffold containing P. purpureum and PLA was produced using the solvent casting and particulate leaching method. P. purpureum fibre, also locally known as Napier grass, is composed of 46% cellulose, 34% hemicellulose, and 20% lignin. PLA composites with various P. purpureum contents (10%, 20%, and 30%) were prepared and subsequently characterised. The morphologies, structures and thermal behaviours of the prepared composite scaffolds were characterised using field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The morphology was studied using FESEM; the scaffold possessed 70-200µm-sized pores with a high level of interconnectivity. The moisture content and mechanical properties of the developed porous scaffolds were further characterised. The P. purpureum/PLA scaffold had a greater porosity factor (99%) and compression modulus (5.25MPa) than those of the pure PLA scaffold (1.73MPa). From the results, it can be concluded that the properties of the highly porous P. purpureum/PLA scaffold developed in this study can be controlled and optimised. This can be used to facilitate the construction of implantable tissue-engineered cartilage.

Sleep, ageing and stroke--newer directions in management of stroke.

Stroke is a serious health problem and is chiefly a disorder of the elderly population. Several modifiable and non modifiable risk factors have been studied. The association of sleep disorders and stroke is exciting. Obstructive sleep apnea (OSA) which is now considered a systemic disease significantly increases the risk of stroke and death from any cause and the increase is independent of other risk factors including hypertension. There is high prevalence of OSA in the elderly. OSA affects the cerebral hemodynamics adversely. There appears to be a bi-directional relation between sleep disordered breathing(SDB) and cerebrovascular accidents. Strokes can themselves generate SDB. The presence of OSA in stroke patients is associated with poor outcome. Cyclical hypoxia and sympathetic stimulation has deleterious effects on cardiovascular, cerebrovascular and metabolic functions. The effects are particularly important in existing ischemic brain injury. Use of continuous positive pressure in OSA patients is rewarding. We propose that feeding through Ryle's tube may compromise with the patency of pharynx during sleep times and therefore this must be considered in management guidelines for stroke.