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Landsat TM and ETM+ images were used to examine urban growth for the Greater Cairo area, Egypt, between 1986 and 1999, assisted by fieldwork and high spatial resolution images such as IRS, CORONA, and IKONOS. During the study period, urban land (collectively classified as built-up surface) increased significantly. Most of the increases in urban land came from the conversion of desert land and farmland on the Nile Delta. When changes in built-up surface were analyzed against census data of 1986 and 1996, it was found that population per unit area of built-up surface may serve as a good indicator of urbanization. This metric offers a different measure from the traditional calculation of population density and provides a measure of urban living environment by reflecting the dynamics of both population and urban land use growth. For the entire study area, population density increased by 26.8% from 7158 persons/km 2 to 9074 persons/km 2 during 1986–1999. In the mean time, the total built-up area increased by 33.7% from 344.4 km 2 to 460.4 km 2 , while population per unit of urban land decreased from 27,188 persons/km 2 to 25,799 persons/km 2 , indicating that urban land use growth in terms of construction and infrastructure may have outpaced population growth in Cairo overall. However, such changes were not evenly distributed. While most increases in built-up surface were found in the outer margin of the greater Cairo area, population per unit built-up area increased most significantly in the suburbs and to the south of the city. Such changes reflected the nature of housing demand and the mechanisms that governed the urbanization process in the Greater Cairo area.

The aim was to evaluate the radioprotective properties of recombinant human fibroblast growth factor 20 (FGF-20; CG53135-05) in vitro and in vivo and to examine its effects on known cellular pathways of radioprotection. Relative transcript levels of the cyclooxygenase 2 (COX2), Mn-super oxide dismutase (SOD), CuZn-SOD, extracellular (EC)-SOD, nuclear respiratory factor 2 (Nrf2), glutathione peroxidase 1 (GPX1) and intestinal trefoil factor 3 (ITF3) genes, which are involved in radiation response pathways, were assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) in NIH/3T3, IEC18, CCD-18Co, CCD-1070sk and human umbilical vein endothelial cells (HUVEC) cells exposed to FGF-20. Activation of the radioprotective signal transduction pathways initiating with the serine/threonine Akt kinase and the extracellular regulated kinase (ERK) were analysed. Levels of intracellular hydrogen peroxide and cytosolic redox potential were also measured in irradiated and unirradiated cells in the presence or absence of FGF-20. The effects of FGF-20 on cell survival in vitro following ionizing radiation were evaluated using clonogenic assays. To test the potential activity of FGF-20 as a radioprotectant in vivo, mice were administered a single dose of FGF-20 (4 mg kg(-1), intraperitoneally (i.p.) 1 day before lethal total-body irradiation and evaluated for survival. In vitro exposure to FGF-20 increased expression of the Nrf2 transcription factor and oxygen radical scavenging enzymes such as MnSOD, activated signal transduction pathways (ERK and Akt) and resulted in increased survival of irradiated cells in vitro. FGF-20 treatment also resulted in a concomitant reduction in intracellular levels of injurious reactive oxygen species (ROS) following acute ionizing irradiation. Finally, prophylactic administration of FGF-20 to mice before potentially lethal, whole-body X-irradiation led to significant increases in overall survival. FGF-20 reduced the lethal effects of acute ionizing radiation exposure in cells by up-regulating important signalling and free radical scavenging pathways. Survival-sparing effects of FGF-20 prophylaxis in acutely irradiated mice presumably are elicited by comparable mechanisms. These results indicate that FGF-20, has significant radioprotective attributes with potential applications in clinical and non-clinical exposure settings.

This article examines growth in the extent of Cairo's urban area and changes in population distribution between 1986 and 1996. It includes a quantitative assessment of urban growth and changing patterns of population density in the city's administrative sub-districts. In a unique contribution to the available research on Cairo, the population density for the built-up area of the census units is calculated, giving much greater insight into the city's growth than previous research that calculated density based on census units in their entirety. The study finds significant population decentralisation taking place and discusses the possible implications if this trend continues.