Comparative alterations in p53 expression and apoptosis in the irradiated rat small and large intestine.

Temporal and spatial relationships between radiation-induced apoptosis and expression of p53 mRNA and protein were compared in rat small and large intestine. Apoptosis was quantified using morphological criteria, and p53 expression determined by immunohistochemistry or whole-tissue Northern analysis. In the small intestine, peak levels of apoptosis appeared earlier (4 h) than in the large intestine (6 h). p53 mRNA transcript levels in small and large intestine were not significantly altered from control levels at any time after treatment. However, in treated small and large intestine, cells showed increased positivity for p53 protein, increasing 10-fold over control levels 4-5 h after irradiation. A strong spatial relationship was found between high incidence apoptosis and p53 protein positivity. We compared published data of stem cell population positions for small and large intestine with our results. Target cells for apoptosis and p53 expression occurred at approximately fifth position from the crypt base of the small intestine, a zone coincident with stem cell population. Target cell position for apoptosis and p53 expression in the large intestine was again at fifth or sixth position from the base, but this zone is not the reported stem cell position (first or second position) for large intestine. Results from our model of radiation-induced intestinal apoptosis indicate that p53 protein is closely associated both temporally and spatially with the induction of apoptosis, and support the work of others in suggesting that p53 expression is modulated post-transcriptionally. Furthermore, our results support a hypothesis that apoptotic targeting of damaged stem cell populations, early response for apoptotic removal of DNA-damaged cells and/or early repair of these damage cells are all important parameters that determine differences in levels of tumorigenesis in the small and large intestine

Morphologic, biochemical, and molecular evidence of apoptosis during the reperfusion phase after brief periods of renal ischemia.

A multiparametric analysis to demonstrate that even brief periods of arterial clamping can initiate extensive cell loss in a rat kidney through the process of apoptosis during the 48-hour period after reperfusion was performed. Microscopic examination of rat renal tissues subject to a 5-, 30-, or 45-minute period of complete ischemia showed the presence of apoptotic bodies both within and occasionally between renal tubules, appearing as early 12 hours after reperfusion, and increasing in numbers at 24 hours. Furthermore, DNA extracted from such reperfused renal tissue demonstrated the appearance of a distinct "ladder" pattern of DNA fragments after electrophoresis in agarose gels, a phenomenon commonly associated with cells undergoing apoptosis and in contrast to the predominant smear pattern obtained after electrophoresis of DNA extracted from necrotic renal tissue. Finally, messenger RNA (mRNA) encoding sulfated glycoprotein-2, a gene product previously identified to apoptotic renal cells, was found to be highly expressed in the 30-minute arterial clamped rat kidney after 24 hours of reperfusion, but was not detectable in mRNA extracted from renal tissue after 24 hours chronic infarction. This study demonstrates that a combination of morphologic, biochemical, and molecular markers can be used to distinguish predominant modes of cell death in varying forms of tissue injury. Application of these analytical techniques to renal vascular injury has distinguished that brief periods of complete ischemia initiates a form of cell death (apoptosis) during a subsequent reperfusion phase that is drastically different from cellular necrosis induced by prolonged severe ischemia

Apoptosis in vascular endothelial cells caused by serum deprivation, oxidative stress and transforming growth factor-?

Vascular endothelial cell apoptosis has previously been shown to play a role in the pathogenesis of hypertension-induced vessel deletion and damage. In the present in vitro study we analyse several possible relevant causative factors of vascular endothelial cell apoptosis, namely, serum deprivation and nutrient depletion, oxidative stress in the forms of hypoxia, hyperoxia or free radical damage, and altered levels of transforming growth factor-beta 1 (TGF-beta 1) protein. An established cell line, bovine aortic endothelial cells (BAEC), was maintained in complete growth medium (RPMI-1640 plus 15% fetal calf serum and antibiotics, abbreviated as RPMI) in 25cm(2) flasks or in 12-well plates on glass coverslips. Confluent but actively-growing cultures were treated with either hypoxia (PO2 of RPMI = 50mmHg), serum-free media (SFM), SFM plus hypoxia, hyperoxia (PO2 of RPMI = 450mmHg), hydrogen peroxide (H2O2, 1 mM) in SFM, or TGF-beta 1 protein (10ng/mL) in SFM. Appropriate control Cultures were used. BAEC were collected 48h or 72h after all treatments except for TGF-beta 1 and H2O2 treatments that were collected at 16-18h. Cell death was assessed using morphological characteristics or in situ end labeling (ISEL), cell proliferation assessed using proliferating cell nuclear antigen (PCNA), and TGF-beta 1 expression assessed using transcript levels or immunohistochemistry. All treatments significantly increased levels of apoptosis over control cultures (

Urban atmospheres as brandscapes and lived experiences

In recent years the concept of urban atmosphere seems to appear everywhere – discussed as a marketing strategy, part of an eventscape, a crucial element in place-marketing or a key feature in the production of brandscapes. An attractive city should contain settings with attractive atmosphere or ambiance. This paper discusses what we can learn from this rapid expansion. What happens when the elusive phenomenon of atmospheres becomes part of planning and performance in new and old cities? Atmospheres are difficult to pre-fabricate, to sustain or control. Drawing on an ongoing research project on the making and un-making of urban atmospheres I will discuss different approaches to the study of such sensory landscape. I track the travels of the concept of atmosphere both in academic research and among practitioners in city planning and branding. Two cases of intensive branding in Denmark and Sweden are followed as they are transformed over a decade of city development