[Three dimensional culturing of human jaw osteoblasts in PLLA/HA scaffold]

Tissue engineering using somatic cells and synthetic extracellular matrix [scaffold] represents a new approach for regeneration of mineralized tissue and bone. This study was carried out to investigate the ability of a PLLA/HA scaffold to culture osteoblast cells in a three dimensional milieu. Three bony samples were taken from extraction sites during surgical extraction of wisdom teeth. Osteoblasts were obtained from specimens by using trypsin and collagenase and were cultured in monolayer up to passage four. Cells were seeded on PLLA/HA scaffolds at density of 106 cells/ml and then incubated for 21 days. The seeded cells were evaluated by Hoechst, von kossa and H and E stainings and scanning electron microscopy. Cellular growth was more pronounced when isolation was carried out by collagenase. According to scanning electron microscopy, osteoblast cells had been proliferated and attached to the scaffolds. H and E, Hoechst and von kossa stainings confirmed the presence of the harvested cells in the scaffold too. Our findings suggest that osteoblast cells can grow onto PLLA/HA scaffold in vitro

Hearing loss in 7 to 11 years old school boys of Mashhad without recognized ear problems: 2006

The aim of this research was to determine the prevalence of hearing impairments and its associations with different ear problems among schoolboys in Mashhad, Iran. In this cross sectional research, a representative sample of 1047 schoolboys [between age group 7 to 11 years] was subjected to diapason tests, Otoscopic examination and questionnaire. Then in the next step, suspected cases were visited by an Ear, Nose and Throat [ENT] specialist and subjected to Pure Tone Audiometry [PTA]. Data analysis identified 29 children with hearing impairment [72.1% mild, 20.9% moderate, and 2.3% severe and4.7% profound] making a prevalence of 2.76% [60.4% conductive, 27.9% sensorineural and 11.7% mixed hearing impairment].Data analysis revealed ear problems with the following prevalence's: ear wax [13.7%], otalgia [11%], ear trauma [5.3%] and ear washing [3.6%]. The prevalence of hearing impairment was comparable to that in developed countries, but was better than that in developing countries